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Poster papers

THEME 1: ENVIRONMENT, ECOSYSTEM BIOLOGY, HABITAT AND DIVERSITY, OCEANOGRAPHY

Deep-sea fish diversity around Taiwan, Province of China

H.M. Yeh1, M.L. Chiou2, Y.C. Liao3, H.C. Ho4, T.H. Wu1, P.F. Lee3 and C.H. Chang4, K.T. Shao1

1 Institute of Zoology, Academia Sinica, Taiwan, Province of Chine
2 Institute of Zoology, National Taiwan University, Taiwan, Province of Chine
3 Institute of Oceanography, National Taiwan University, Taiwan, Province of Chine
4 Institute of Marine Biology, National Taiwan Ocean University, Taiwan, Province of Chine

Corresponding author: K. T. Shao
Laboratory of Fish Ecology & Evolution, Institute of Zoology
Academia Sinica, Nankang, Taipei, Taiwan 115, Province of China

1. INTRODUCTION

Taiwan, Province of China1 is adjacent to the Taiwan Strait Shelf, the South China Sea Basin, the West Philippine Sea Basin and the Okinawa Trough (Figure 1). More than half of the sea territory of Taiwan are deep basins down to nearly 5000 m and are the largest habitat around Taiwan. The shallow-water fishes of Taiwan have been well documented by Shen et al. (1993), but the deep-sea fish fauna are yet to be fully investigated. The same situation holds true for the fishes of the South China Sea. After the huge collections of shallow-water and deep-sea fishes by the U.S. research vessel Albatross in Philippine seas and adjacent waters during the years 1907–1910, the shallow-water fishes of the South China Sea have been relatively well documented (Randall and Lim 2000), but the data of deep-sea fishes are scarce. Okamura et al. (1984, 1985) provide a list of the shallow-water and deep-sea fishes of the Okinawa Trough. However, few samples were collected from the Taiwan area.

The ‘water mass hypothesis’ (Koslow, Bulman and Lyle 1994) explains the vertical and horizontal patterns of the deep-sea demersal fish communities. Therefore, the community structures of the deep-sea demersal fish are supposed to be different between the South China Sea and the adjacent waters.

To better understand the marine bioresource and diversity, it is critical to explore the deep-sea fauna in Taiwan. The short-term objective of this study is to explore the faunistical composition, abundance, biomass and diversity of deep-sea fishes in the waters around Taiwan. The long-term objectives are (a) to compare the community structure of deep-sea fishes inhabiting the South China Sea, the West Philippine Sea and the Okinawa Trough, (b) to detect the general trends in the distribution of the fish fauna in relation to the environmental variables and (c), to compare the boundaries between the faunal zones of deep-sea fishes with those water masses.

1 To facilitate reading of this report, “Taiwan, Province of China”will be subsequently referred to as “Taiwan”.

2. MATERIALS AND METHODS

The deep-sea fish fauna around Taiwan was investigated from the samples collected by the R.V.Ocean Researcher I under a three-year project (August 2002 – July 2004) of the National Science Council. Because of the limitation of the trawl wire length, only depths less than 3570 m were surveyed during the six cruises using a semi-balloon otter trawl with a 22 m headrope, a 2.5 cm stretched-mesh net body and a 1.3 cm stretched-mesh codend. A French type beam trawl of 4 m span, a rock dredge of 1 m span and Isaacs-Kidd midwater trawl (IKMT) were also used. One-hour tows were usually used for the operation of bottom trawl except when abnormally high tension of the tow wire was encountered during a trawl operation. The distance swept by the trawl was estimated from the position where the trawl contacted the sea bottom to where it left, using an integrated navigation system. The towing speed of otter trawl was kept between 1.5 and 2.5 knots over-the-ground speed and that of the beam trawl between 1.0 and 1.5 knots.

FIGURE 1
Sea floor topography around Taiwan

FIGURE 1

After recovery of the trawl, all of the samples were identified to main taxa. Fishes were preserved in a -20° C deep freezer. In the laboratory, the samples were identified to species if possible. The morphometric characters, e.g. size and weigh, of fish was measured and recorded. Specimens were then fixed in 10% neutralized formalin for more than 4 weeks. After fixing, the samples were rinsed with tap water and then preserved in 70% alcohol. The Shannon-Wiener index (natural logarithm base) was chosen to calculate fish diversity in each haul.

3. RESULTS AND CONCLUSIONS

A total of 21 otter trawl stations, 23 beam trawl stations, 7 dredge stations and eight IKMT stations were undertaken during the first two years (Figure 2). One thousand four hundred and seventy-five fishes belonging to 192 species were caught. Four new species (Oneirodes pietschi, Bufoceratis shaoi, Caelorinchus sheni and Caelorinchus leptorhinus), five possible new species (two Oneirodidae, one Gigantactinidae and one Dalatiidae - Figure 3) and 86 new records for Taiwan were added to the Taiwan fish fauna from the samples collected by these surveys. These new records include three species of Rajidae (Bathyraja sp., Bathyraja bergi and Pavoraja sp.), two Dalatiids (Centroscyllium kamohar and Etmopterus brachyurus), a Scyliorhinidae (Apristurus japonicus), two Nettastomatids (Venefica tentaculata and Nettastoma parviceps), a Nemichthyid (Avocettina infans), a Muraenesocid (Congresox talabonoides), three Congrids (Gnathophis nystromi ginanago, Rhechiasretrotincta and Ariosoma meeki), two Synaphobranchids (Synaphobranchus sp. and S.brevidorsalis), a Serrivomerid (Serrivomer sp.), seven Sternoptychids (Argyropelecus gigas, A.hemigymnus, Polyipnus danae, P.triphanos complex, Sternoptyx diaphana, S. obscura and S. pseudobscura), a Neoscopelid (Neoscopelus porosus), a Microstomatid (Nansenia ardesiaca), four Gonostomatids (Cyclothone atraria, C.psendopallida, Sigmops atlanticum and S. elongatum), six Stomiids (Astronesthes lucifer, Flagellostomias sp., Stomias nebulosus, Photostomias guernei, Eustomias sp., Leptostomias sp. and Borostomias elucens), a Phosichthyid (Polymetme corythaeola), five Alepocephalids (Alepocephalus longiceps, Talismania okinawaensis, Conocara macroptera?, Rouleina guentheri and R.watasei), two Melamphaids (Poromitra oscitans and Scopeloberyx robustus), a Ceratiid (Ceratias sp.), a Himantolophid (Himantolophus sp.), a Linophrynid (Linophryne indica), a Melanocetid (Melanocetus murrayi), two Oneirodids (Oneirodes sp.2 and Oneirodes sp.3), a Ipnopid (Bathypterois guentheri), a Halosaurid (Halosauropsis macrochir), 20 Macrourids (Gadmus colletti, Bathygadus antrodes, B.nipponicus, B.garretti, Hymenogadus gracilis, Hymenocephalus lethonemus, Nezumia condylura, Pseudoctenurous septifer, Kumba japonica, Sphagemacrurus, seven species of the genus Ventrifossa (Ventrifossa longibarbata, V. macroptera, V. rhipidodorsalis, V. saikaiensis, V. lucifor, V. divergens, V. atherodon) Caelorinchus productus, C. longissimus, C. asteroids and Coryphaenoides microps), a Morid (Gadella jordani), ten Ophidiids (Monomitopus pallidus, M. kumae, Holcomycteronus sp., Alcockia rostrata, Bassozetus glutinosus, Bathyonus caudalis, Dicrolene tristis, Glyptophidium japonicum, Homostolus acer and Porogadus guentheri), a Trachichthyid (Hoplostethus melanopus), a Diretmid (Diretmoides pauciradiatus), a Sebastid (Helicolenus fedorovi) an Ereuniid (Ereunias grallator) and a Zoarcid (Bothrocara molle). These data also filled the gaps in worldwide knowledge of the deep-sea fish fauna between Japan and Philippines.

FIGURE 2
Location of sampling stations

FIGURE 2

FIGURE 3
New species and possibly new species

FIGURE 3

Among the 192 species of deep-sea fishes, 121 species are demersal fishes and 71 species are midwater fishes. Only 31 species of demersal fishes were caught from the Western Pacific Ocean (WP), 72 species were from the South China Sea (SCS) and eighteen species were common in both seas (Table 1). The diversities of deep-sea demersal fishes in the South China Sea are about two times higher than those in the West Pacific Ocean in the depths less than 500 m. However, the diversities between the two seas are nearly the same when the depth is greater than 500 m (Figure 4). The faunal diversity in the South China Sea displays a dramatic decline with depth, but that in the Western Pacific Ocean displays only a general decline with depth. The higher diversity of deep-sea demersal fish found less than 500 m in depth and the dramatic decline of diversity in the South China Sea could be due to the shallower nutricline and the two-fold higher concentration of chlorophyll in the surface waters of the South China Sea compared to that of the Western Pacific Ocean (Liu et al. 2002). The thorough mixing of the South China Sea and the Western Pacific Ocean intermediate water (Chen and Huang 1996) could explain why the diversities of deep-sea demersal fish between the South China Sea and the Western Pacific Ocean in seas greater than 500 m depth are similar.

FIGURE 4
Diversities of demersal fish between the South China Sea and the West Pacific Ocean along the depth

FIGURE 4

The quantitative data of all collections as well as the specimen photos of almost all species were digitalized and archived in the web-accessible GIS database -Fauna and Distribution Database of Deep-sea Organism of Taiwan <http://webgis.sinica.edu.tw/seafish/viewer.htm for public access>. The database was also connected with Fish Database of Taiwan <http://fishdb.sinica.edu.tw/>.

In conclusion, four new species (Oneirodes pietschi, Bufoceratis shaoi, Caelorinchus sheni and Caelorinchus leptorhinus), five possible new species (two Oneirodids, one Gigantactinid and one Dalatiid) and 86 new records of Taiwan were added to the Taiwan fish fauna from the samples collected by the R.V. Ocean Researcher I during the three-year project (August 2002 – July 2004) of the National Science Council.

TABLE 1
Species of demersal fishes caught in the South China Sea (SCS) and the Western Pacific Ocean (WP)

FamilySpeciesSCSWP
AcropomatidaeSynagrops japonicus* 
AlepocephalidaeAlepocephalus bicolor**
 Alepocephalus longiceps* 
 Bajacalifornia erimoensis* 
 Conocara sp. (macroptera?) *
 Rouleina guentheri *
 Rouleina watasei* 
 Talismania okinawaensis* 
AnacanthobatidaeAnacanthobatis borneensis* 
AploactinidaeErisphex pottii *
BothidaeBothus myriaster* 
CentrophoridaeDeania calcea *
ChaunacidaeChaunax abei* 
ChimaeridaeChimaera phantasma *
ChlorophthalmidaeChlorophthalmus acutifrons* 
CongridaeAriosoma meeki* 
 Gnathophis nystromi ginanago**
 Rhechias retrotincta *
 Bathycongrus retrotinctus* 
CynoglossidaeSymphurus hondoensis* 
 Symphurus novemfasciatus *
 Symphurus strictus**
DalatiidaeCentroscyllium kamohari *
 Etmopterus brachyurus* 
 Etmopterus lucifer**
DiretmidaeDiretmoides pauciradiatus* 
 Diretmus argenteus* 
EreuniidaeEreunias grallator* 
GonorynchidaeGonorynchus abbreviatus *
MacrouridaeBathygadus sp.* 
 Bathygadus spongiceps *
 Caelorinchus aconcagus* 
 Caelorinchus anatirostris* 
 Caelorinchus brevirostris *
 Caelorinchus cingulatus* 
 Caelorinchus formosanus* 
 Caelorinchus kishinouyei* 
 Caelorinchus macrorhychus* 
 Caelorinchus occa* 
 Caelorinchus smithi* 
 Caelorinchus sp.**
 Cetonurus robustus* 
 Chalinura sp.**
 Coryphaenoides marginatus* 
 Coryphaenoides microps**
 Coryphaenoides nasutus *
 Coryphaenoides sp.* 
 Gadomus colletti* 
 Hymenocephalus lethonemus* 
 Hymenocephalus longiceps* 
 Hymenocephalus sp. *
 Hymenocephalus striatissimus *
 Hymenogadus gracilis* 
 Malacocephalus laevis**
 Mataeocephalus sp.* 
 Nezumia condylura**
 Nezumia sp.* 
 Nezumia spinosa* 
HalosauridaeHalosauropsis macrochir**
IpnopidaeBathypterois guentheri* 
MacrouridaeBathygadus antrodes**
 Bathygadus garretti* 
 Trachonurus sulctus* 
 Ventrifossa ctoenomelas* 
 Ventrifossa garmani**
 Ventrifossa longibarbata* 
 Ventrifossa macroptera* 
 Ventrifossa nigrodorsalis* 
 Ventrifossa rhipidodorsalis**
 Ventrifossa saikaiensis* 
 Ventrifossa sp.* 
MoridaeGadella jordani**
MuraenesocidaeCongresox talabonoides* 
 Gavialiceps taiwanensis *
NeoscopelidaeNeoscopelus microchir* 
 Neoscopelus porosus* 
NettastomatidaeSaurenchelys fierasfer *
 Venefica tentaculata *
OphichthidaePisodonophis cancrivorus* 
OphidiidaeBassozetus glutinosus *
 Bathyonus caudalis* 
 Dicrolene tristis* 
 Glyptophidium japonicum* 
 Holcomycteronus sp. *
 Monomitopus kumae* 
 Monomitopus pallidus* 
 Neobythites sivicola* 
 Neobythites sp.* 
 Neobythites sp.1* 
 Neobythites stigmosus**
 Sphagemacrurus pumiliceps *
 Sphagemacrurus richardi* 
 Squalogadus modificatus* 
 Trachonurus sp.* 
OphidiidaePorogadus guentheri *
 Alcockia rostrata* 
 Homostolus acer* 
ParalichthyidaePseudorhombus sp.* 
PeristediidaePeristedion orientale* 
 Satyrichthys amiscus* 
RajidaeBathyraja bergi *
 Pavoraja sp.* 
 Bathyraja sp.**
ScyliorhinidaeApristurus japonicus *
 Apristurus macrorhynchus *
 Galeus eastmani* 
 Galeus sauteri* 
 Parmaturus melanobranchus**
SebastidaeHelicolenus fedorovi *
 Helicolenus hilgendorfii *
SetarchidaeSetarches longimanus**
SparidaeDentex tumifrons *
SynaphobranchidaeSynaphobranchus affinis *
 Synaphobranchus brevidorsalis *
 Synaphobranchus kaupii* 
 Synaphobranchus sp. *
SynodontidaeHarpadon microchir**
TetraodontidaeSphoeroides pachygaster* 
TrachichthyidaeHoplostethus crassispinus* 
 Hoplostethus melanopus* 
ZoarcidaeBothrocara molle *

4. ACKNOWLEDGEMENTS

We thank the captain and crew of R.V. Ocean Researcher I for their cooperation and assistance during the cruises. We also acknowledge the support of the National Science Council for funding this three-year project.

5. LITERATURE CITED

Chen, A. C.-T. & M.-H. Huang 1996. A mid-depth front separating the South China Sea Water and the Philippine Sea Water. Journal of Oceanography, 52 : 17–25.

Koslow, J.A., C.M. Bulman & J.M. Lyle 1994. The mid-slope demersal fish community off Southeastern Australia. Deep-Sea Research, 41: 113–141.

Liu, K.-K., S.-Y. Chao, P.-T. Shaw, G.C. Gong, C.-C. Chen & T.Y. Tang 2002. Monsoon-forced chlorophyll distribution and primary production in the South China Sea: observations and a numerical study. Deep-Sea Research I, 49 : 1387–1412.

Okamura, O., Y. Machida, T. Yamakawa, T. Yatou, K. Nakaya & T. Kitajima 1984. Fishes of the Okinawa Trough and the adjacent waters I. Japan Fisheries Resource Conservation Association, Tosho Printing, Tokyo.

Okamura O., Y. Machida, T. Yamakawa, K. Matsuura & T. Yatou 1985. Fishes of the Okinawa Trough and the adjacent waters II. Japan Fisheries Resource Conservation Association, Tosho Printing, Tokyo.

Randall J.E. & K.K.P. Lim 2000. A checklist of the fishes of the South China sea. The Raffles Bulletin of Zoology 2000 Suppl 8 : 569–667.

Shen S.C., S.C. Lee, K.T. Shao, H.K. Mok, C.T. Chen & C.H. Chen 1993. Fishes of Taiwan. Department of Zoology, National Taiwan University, Taipei.

Distribution and length-weight compositions of some rare deep-sea fishes from Oreosomatidae, Notacanthidae, and Zoarcidae families in the Pacific waters off the northern Kuril islands and southeastern Kamchatka, Russia

A.M. Tokranov1, A.M. Orlov2 and I.A. Biryukov3
1 Kamchatka Branch of Pacific Institute of Geography (KPBIG) 6, Partizanskaya, Petropavlovsk-Kamchatsky, 683000, Russia
<tok@mail.iks.ru>

2 Russian Federal Research Institute of Fisheries & Oceanography (VNIRO) 17, V. Krasnoselskaya, Moscow, 107140, Russia
<orlov@vniro.ru>

3 Sakhalin Research Institute of Fisheries & Oceanography (SakhNIRO) 196, Komsomolskaya, Yuzhno-Sakhalinsk, 693016, Russia
<bia@sakhniro.ru>

1. INTRODUCTION

Several research and fishing cruises were conducted off the North Kuril Islands and South East Kamchatka in 1993–2002. Data were collected on the composition of bottom fish communities in the lower part of the shelf and upper bathyal and on the distribution pattern and biology of local species. The occurrence of some rare ichthyofauna was also recorded. This paper presents information on the spatial and bathymetrical distribution, size and weight frequency data for four little-studied fish species: coster dory (Allocyttus verrucosus, Oreosomatidae), spiny eel (Notacanthus chemnitzii, Notacanthidae), (Hadropogoonichthys lindbergi) and tough eelpout (Puzanovia rubra, Zoarcidae).

2. MATERIAL AND METHODS

The material for this paper was collected during 44 research and fishing cruises on the Pacific side of the North Kuril Islands and South East Kamchatka (47° 50'–52° 10' N, Figure 1) in April–December 1993–2002. Over 8000 bottom trawl hauls at 100–850 m were made. The bottom temperature was measured during a trawling in most cruises. The hauls were made during the day and night using bottom trawls with a vertical and horizontal opening of 5–6 m and 25 m respectively. Average towing speed was 3.6 knots. Trawl opening was monitored using special equipment. Hauling duration varied between 0.5 and 10 hours so catches were then recalculated to a standard one-hour haul. The percentage presence of each species was analyzed by depth and bottom temperature. The size and weight data were based on length and weight measurements of 31 coster dory, 31 spiny eel, 8 H. lindberg and 7 tough eelpout.

FIGURE 1
Map of the study area

FIGURE 1

3. RESULTS AND DISCUSSION

The frequency of occurrence and catch volume data indicate that the abundance of all four species off the North Kuril Islands in the Pacific and near the South East Kamchatka is low (Table 1). Most often they jointly inhabit the sites with the more abundant species within the bathymetric range of their catches (Table 2).

TABLE 1
Quantitative indices characterizing the occurrence of the rare species Oreosomatidae, Notacanthidae, and Zoarcidae in the catches off the northern Kuril Islands and southeastern Kamchatka, 1993–2002

Species% weight in catchesNo. of individualsNo. per hour trawlingTotal weight (kg)Weight/h trawling (kg)Number of trawls with specimens
Coster dory
(Allocyttus verrucosus)
0–0.353
<0.001
1–3
1.15
0–4
0.31
0–1.80
0.96
0–1.60
0.42
26
Spiny eel
(Notacanthus chemnitzii)
0–1.156
<0.001
1–5
1.35
0–4
0.50
0–2.00
0.56
0–3.00
0.44
26
Eelpout
(Hadropogonichthys lindbergi)
0–0.256
<0.001
1–2
1.14
0–1
0.28
0–0.12
0.08
0–0.10
0.03
7
Tough eelpout
(Puzanovia rubra)
0–0.008
<0.001
1
1.0
0–2
0.43
0–0.20
0.09
0–0.24
0.07
7

Note: Above line: minimum and maximum values, under line, mean value.

TABLE 2
Species composition of catches containing rare species of families Oreosomatidae, Notacanthidae, and Zoarcidae off the northern Kuril Islands and southeastern Kamchatka, 1993–2002

SpeciesA. verrucosusN. chemnitziiH. lindbergiP. rubra
Aleutian skateBathyraja aleutica57.7+++
Whiteblotched skateB. maculata+57.7100.057.1
Matsubara skateB. matsubarai+53.8++
Giant grenadierAlbatrossia pectoralis84.680.857.1+
Popeye grenadierCoryphaenoides cinereus73.188.5-+
Pacific flatnoseAntimora microlepis65.4++-
Walleye pollockTheragra chalcogramma++57.171.4
Atka mackerelPleurogrammus monopterygius++57.1+
Pacific Ocean perchSebastes alutus+50.057.171.4
Shortraker rockfishS. borealis96.276.971.4+
Shortspine thornyheadSebastolobus alascanus80.850.0+-
Broadbanded thornyheadS. macrochir92.396.285.771.4
Whitebar eelpoutLycodes albolineatus57.7+85.7+
Blackfin hooker sculpinArtediellichthys nigripinnis++57.1-
Longfin Irish lordHemilepidotus zapus+++57.1
Blacknose sculpinIcelus canaliculatus+65.457.1-
Spectacled sculpinTriglops scepticus++57.1+
Darkfin sculpinMalacocottus zonurus84.692.3100.085.7
Blackfin poacherBathyagonus nigripinnis+61.5++
Sawback poacherSarritor frenatus+61.585.7+
Unidentified snailfishCareproctus cf. cyclocephalus+57.7++
Forktail snailfishC. furcellus65.480.871.457.1
Round snailfishC. roseofuscus++71.457.1
SnailfishElassodiscus obscurus+50.0-+
Dimdisc snailfishE. tremebundus65.480.8100.0+
Kamchatka flounderAtheresthes evermanni92.396.271.471.4
Roughscale soleClidoderma asperrimum65.4+--
Pacific black halibutReinhardtius hippoglossoides matsuurae88.573.1-+

Note: Table contains data only for species with frequency of occurrence in tows of 50% and more, «+» : less than 50%, «-» : the lack of species i catches.

3.1 Occurrence and spatial/bathymetric distribution

Current data show coster dory to be widely distributed in world oceans (James, Inada and Nakomura 1988, Du Buitt and Quer 1993, Karrer 1990, Cabezas and Risso 1997, Quero, Du Buitt and Vayne 1997, 2000, Lindsay et al. 2000). In certain areas this species may be highly abundant and is considered a fishery target. In Australian waters coster dory is a common bycatch of orange roughy (Hoplostethus atlanticus) fisheries (Lyle, Riley and Kitchener 1992). Off New Zealand this species is fished with dories (Fincham, McMillan and Ito 1991). In the western Indian Ocean (off Aghullas banks) in the mid-1990s estimated biomass of coster dory was about 300 000 t and daily catches per vessel reached 35 to 50 tonnes. Annual available catch was estimated as 50 000 t (Budnichenko, Johnson and Hart 1998). In the North Pacific this species occurs from Honsu and California to the Gulf of Alaska and Bering Sea where it is caught occasionally (Welander, Johnson and Hart 1957, Kobayashi, Mikawa and Ito 1968, Maruyama 1970, Fedorov 1973, 2000, Eschmeyer, Herald and Hamman 1983, Masuda et al. 1984, Amaoka, Toyoshima and Inada 1995, Orlov 1998, Orlov, Moukhametov and Volodin 1998, Fedorov and Parin 1998, Moukhametov and Volodin 1999, Borets 2000, Sheiko and Fedorov 2000, Mecklenburg, Mecklenburg and Thorsteinson 2002). Coster dory is probably transported incidentally to these areas by deepwater currents during periods of warming.

FIGURE 2
Capture sites of coster dory in the Pacific waters off the northern Kuril Islands and southeastern Kamchatcka, 1993–2002
(lines are 100, 200, 500 and 1 000 m isobaths)

FIGURE 2

In 1993–2002 the dory in the Pacific waters of the North Kuril Islands and South East Kamchatka was recorded nearly every year in the survey area, from 47°50' to 52°00' N (Figure 2) though its actual catches did not exceed 1 or 2 individuals during a 4–8 hour tow; only one catch of three of these species was recorded (Table 1). According to Sheiko and Fedorov (2000), coster dory is a mesopelagic species inhabiting depths down to 1800m. On the ocean side of the Kuril chain it occurs mostly near the bottom in the range 270–690 m (Fedorov 2000). The analysis of trawl catches showed that in April–December 1993–2002 coster dory was found in catches on the Pacific side of the North Kurils and off the South East Kamchatka at depths of 310–750 m. Bottom temperatures were 2.3–3.6°C. However, over 55 percent of the fish came from the 400–600 m layer (Figure 3). Within Australian waters the maximum species abundance occurred in depths of 900–1200 m (Lyle and Smith 1997). Such differences may relate to the limits of the bathymetric range investigated. In warmer Australian waters the range of coster dory may be shifted to greater depths.

Spiny eel is widely distributed in the world oceans (Blacker 1975, 1977, Jonsson 1976, Jonsson, Merrett 1981, Nakamura et al. 1986, Paxton et al. 1989, Paulin et al. 1989, Sulak 1990). In the North Pacific this species occurs in Asian waters from Hokkaido along the Kuril Islands (including the Sea of Okhotsk) to the East Kamchatka (Eschmeyer, Herald and Hamman 1983, Masuda, Amaoka and Araga 1984, Amaoka, Nakaya and Yabe 1995, Golovan et al. 1989, Golovan, Pakhorukov and Sysa 1990, Dudnik and Dolganov 1992, Orlov 1998, Orlov et al. 1998, Borets 2000, Fedorov 2000, Sheiko and Fedorov 2000). In American waters spiny eel is distributed from California to Oregon (Peden 1976, Eschmeyer, Herald and Hamman 1983, Lea and Rosenblatt 1987, Calliet, Andrews and Wakefield 1999, Mecklenburg, Mecklenburg and Thorsteinain 2002).

FIGURE 3
Bathymetric distribution of coster dory (upper panel) and spiny eel (lower panel) in the Pacific waters off the northern Kuril Islands and southeastern Kamchatka,1993–2002

FIGURE 3
FIGURE 3

Only one specimen of spiny eel was found in 1993–2002, opposite the Fourth Kuril Strait; all other spiny eels were caught to the south, mostly over the slope of the underwater elevated plateau in the northern link of the outer Kuril chain ridge (Figure 4). Actual catches of spiny eel did not exceed 1–2 individuals per 4–8 hour tow; only once were five fish of this species caught (Table 1). Most researchers describe the spiny eel as a bathybenthal species inhabiting the near-bottom in a depth range of 126–3285 m in the North Pacific (Fedorov 2000, Sheiko and Fedorov 2000, Mecklenburg et al. 2002).

It prefers muddy, muddy-sandy, or sandy grounds (Golovan, Pakhorukov and Sysa 1990). This species was recorded in catches off the North Kuril Islands in the Pacific (April–December, 1993–2002) at 210–790 m where bottom temperatures were 2.4–3.9°C. About 90 percent of fish were caught below 500 m (Figure 3), in temperatures over 3°C. H.lindbergi was first described in 1982 and was taken from the North Kuril waters (Fedorov 1982). This species was characterized as rare but widely distributed, mostly within Asian boreal waters from the northern Kuril Islands to Sagami Bay (Anderson 1994, Borets 2000, Fedorov 2000, Sheiko and Fedorov 2000), and also probably in the eastern Sea of Okhotsk (Anderson 1994). In 1993–2002 the eelpout was observed in catches in a limited part of the Fourth Kuril Strait (Figure 5), but only single individuals were caught except in one case when two fish were caught (Table1).

FIGURE 4
Capture sites of spiny eel in the Pacific waters off the northern Kuril Islands and southeastern Kamchatka, 1993–2002 (legends are as for Figure 2)

FIGURE 4

The eelpout is a mesobenthal species found off the Kuril chain at 200–615 m (Fedorov 2000, Sheiko and Fedorov 2000) and in the south in a range of 340–1400 m (Anderson 1994). In these studies it was recorded at 270–548 m, in bottom temperatures of 2.7–3.6°C. Six of the eight individuals were found within 300–500 m at 3.4°-3.6°C.The tough eelpout was described in 1975 (Fedorov 1975) and is characterized as an Asian species with a wide boreal range, from the northwestern Pacific (Cape Navarin and Pribyloff Islands) off Bauers and Shirshov ridges) along the eastern Kamchatka and Kuril Islands to Hokkaido (Cape Erimo), in the sea of Okhotsk and off the Aleutian Islands (Amaoka et al. 1977, 1995, Masuda et al. 1984, Anon. 1993, 1999, Anderson 1994, Borets 2000, Fedorov 2000, Sheiko and Fedorov 2000, Mecklenburg et al. 2002).

FIGURE 5
Capture sites of H. lindbergi in the Pacific waters off the northern Kuril Islands and southeastern Kamchatka, 1993–2002 (legends as for Figure 2)

FIGURE 5

During the study period of 1993–2002 this species was caught only in the southern most region over a limited range (47°52'–48°56' N) mostly on the western slope of the underwater elevation in the left link of the outer ridge of the Kuril chain (Figure 6). The fish were found singularly on rocky ground with tree-like corals (Table 1), i.e. it has a low abundance and a habitat type that is hardly accessible to trawling. Anderson (1994), Sheiko and Fedorov (2000) and Mecklenburg et al. (2002) note that tough eelpout is a mesobenthic species found at 200–800 m. It is frequently observed at 250–350 m. In 1993–2002 this representative of the Zoarcidae family on the Pacific side of the North Kuril Islands was found at 225–733 m in bottom temperatures of 2.6°–4.1°C. Four of the seven individuals were caught in 225–307 m at 2.6°–3.2°C. In the North Bering Sea this species was caught at 320–380 m (Anon. 2000) while at the Aleutian Islands it was caught at depths of 351–488 m and 515–529 m (Anon. 1993).

3.2 The size and weight composition

Coster dory is a relatively large species (known length, 42 cm) -Mecklenburg et al. 2002. On the Pacific side of the North Kuril Islands and South East Kamchatka in 1993–2002, coster dory in trawl catches were 14–42 cm long (35.1 cm on the average) and weighed 100–1300 g (average 900 g) (Figure 7). The bulk of coster dory catches mostly comprised large fish of 34–38 cm (about 65 percent) and 600–1 200 g (over 81 percent). A notable feature is that the length of the dory from other ocean areas is similar. In the southern Indian Ocean catches were represented by fish of lengths 15.3–33.6 cm but mostly in the range 26–34 cm and 320–1000 g (Melnikov 1981). In Australian waters coster dory lengths were in the 15.2–36.5 cm range. For females, 50 percent maturity was reached at a length of 28 cm (Lyle and Smith 1997). The maximum age of this species is estimated to be from 14–15 years (Melnikov 1981) to 130–170 years (Stewart et al. 1995) for fish 34–35 cm long. Thus, coster dory caught off the Kuril Islands and Kamchatka had the maximum known length and was represented mostly by mature fish of older generations.

Spiny eel is characterized by an eel-like body and a length that exceeds 135 cm (Mecklenburg et al. 2002). The size of this species in the Pacific waters of the North Kuril Islands in 1993–2002 ranged from 36 cm to 85 cm (average 53.2 cm) and weighed from 140 to 1000 g (average 395 g) (Figure 7). Fish of 45 to 55 cm length predominated in the catches (about 50 percent), with body weights of 100–500 g (over 77 percent). A spiny eel with a length of 135 cm was caught in the North Atlantic while maximum known sizes of this species in the Kuril Islands waters do not exceed 58–60 cm (Golovan et al. 1989, 1990).

FIGURE 6
Capture sites of tough eelpout in the Pacific waters off the northern Kuril Islands and southeastern Kamchatka, 1993–2002 (legends as on Figure 2)

FIGURE 6

Unlike spiny eel, H.lindbergi is a relatively small fish with an elongated body and a maximum length of 37 cm (Fedorov 1982). The length of H. lindbergi off the North Kurils in 1993–2002 were 24 to 35 cm and weights were 30–100 g. However, fish sized 31–35 cm weighing 80–100 g prevailed (six of the eight individuals taken).

The tough eelpout is a small representative of the family Zoarcidae. It has an elongated, laterally compressed body (Fedorov 1975). Maximum known length of this species is 32.3 cm (Mecklenburg et al. 2002). The length of tough eelpout caught in 1993–2002 on the Pacific side of the North Kurils varied between 22 and 38 cm while body weights were in the range 30–200 g. However, the size of most fish was between 31–38 cm, with weights being between 70–200 g (five out of seven individuals).

The length-weight relationship in the three fish species (except for the H. lindbergi whose length range in the individuals taken was rather limited) were as follows:

coster dory:W = 1.859 × 10-5 L2.9973 (R2=0.886)
spiny eel:W = 7.169 × 10-6 L 2.7244 (R2=0.840)
tough eelpout:W = 1.196 × 10-6 L 3.2610, (R2=0.835)
whereW = body weight (g)
L = body length (cm).

The regression series calculated by the above formulae agreed well with the empirical data and may be used to determine the mean weights as a function of the lengths for the respective species.

FIGURE 7
Length and weight compositions of coster dory and spiny eel in the Pacific waters off the northern Kuril Islands and southeastern Kamchatka, 1993–2002

FIGURE 7
FIGURE 7
FIGURE 7
FIGURE 7

4. CONCLUSION

These data allow us to conclude that the abundance of all four species taken in the Pacific near the North Kuril Islands and the South East Kamchatka is insignificant. In 1993–2003 the coster dory occurred virtually throughout the whole area from 47°50' N to 52°00' N at depths of 310 m – 750 m and bottom temperatures of 2.3°–3.6° C. Over 55 percent of individuals taken in the observed period came from 400–600 m. The spiny eel occurred in catches during those years only in the south of the area surveyed, mostly on the slope of the elevated region of the northern link in the outer ridge of the Kuril chain within 210 m – 790 m where bottom temperatures ranged within 2.4°–3.,9°C. However, by far most of its individuals (about 90 percent) taken during the survey period came from depths greater than 500 m, with temperatures over 3°C. In contrast, the tough eelpout and H. lindbergi were found only in limited numbers on the continental slope of the North Kurils in the Pacific: the former between 48°24'–49°12' N. (270–548 m) with bottom temperatures of 2.7°–3.6°C; and the latter between 47°52'–48°56' N mainly on the western slope of the underwater plateau, at depths of 225 m to 733 m and bottom temperatures of 2.6°–4.1°C. The trawl catches in 1993–2002 contained primarily large individuals of coster dory, tough eelpout and H.lindbergi, with respective lengths and weights of 34–38 cm (600–1200 g), 31–35 cm (80–100 g), and 31–38 cm (70–200 g). In contrast, the catches of spiny eel consisted for the most part of mid-sized fish: 45–55 cm (100–500 g).

5. ACKNOWLEDGEMENTS

We would like to acknowledge the assistance in data sampling from our colleagues at the VNIRO, Russian Federal, KamchatNIRO, Kamchatka, SakhNIRO, Sakhalin Research Institutes of Fisheries and Oceanography and the other organizations participating in research cruises in 1993–2002.

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Blacker, R.W. 1977. English Observations on Rare Fish in 1975. Annales Biologiques, Copenhagen.32 : 184–185.

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Calliet, G.M., A.H. Andrews, W.W. Wakefield et al. 1999. Fish Faunal and Habitat Analyses Using Trawls, Camera Sleds, and Submersibles in Benthic Deep-sea Habitats off Central California. Oceanologica Acta. 22(6) : 579–592.

Du Buit, M.H. & J-C. Quero 1993. First Record in the North-eastern Atlantic of Hoplostethus cadenati (Beryciformes, Trachichthyidae) and Allocyttus verrucosus (Zeiformes, Oreosomatidae). Cybium. 17(1) : 81–82.

Dudnik, Yu.I. & V.N. Dolganov 1992. Distribution and Stocks of Fish on Continental Slope of the Sea of Okhotsk and Kuril Islands, Summer 1989. Voprosy Ikhtiologii. 32(4):83–98 (In Russian).

Eschmeyer, W.N., E.S. Herald & H. Hamman 1983. A Field Guide to Pacific Coast Fishes of North America from the Gulf of Alaska to Baja California. Boston: Houghton Mifflin Company, 336 pp.

Fedorov, V.V. 1973. Ichthyofauna of the Bering Sea Continental Slope and Some Aspects of Its Origin and Formation. Izvestiya TINRO. 87 : 3–41.

Fedorov, V.V. 1975. Description of New Species and Genus of Eelpout Fish Puzanovia rubra, gen. et sp. n. (Pisces, Zoarcidae) from the North Pacific Ocean. Voprosy Ikhtiologii. 15(4) : 587–591 (In Russian).

Fedorov, V.V. 1982. New Eelpout Fish Hadropogonichthys lindbergi Fedorov, gen. et sp. nov. (Zoarcidae) from Bathyal Depths of the Forth Kuril Strait. Voprosy Ikhtiologii. 22(5) : 722–729 (In Russian).

Fedorov, V.V. 2000. Species Composition, Distribution and Habitation Depths of the Northern Kuril Islands Fish and Fish-like Species. In Kotenev, B.N. (Ed). Commercial and Biological Studies of Fishes in the Pacific Waters of the Kuril Islands and Adjacent Areas of the Okhotsk and Bering Seas in 1992–1998. Collected Papers. Moscow: VNIRO, P. 7–41 In Russian).

Fedorov, V.V. & N.V. Parin 1998. Pelagic and bentho-pelagic fishes of the Russian Pacific waters (within the 200-miles EEZ). Moscow: VNIRO Publishing, 154 pp. (In Russian).

Fincham, D.J., P.J. McMillan & A.C. Hart 1991. Catches of Oreos (family Oreosomatidae) in New Zealand Waters, 1972–88. New Zealand Fishery Data Report 38 : 1–58.

Golovan G.A., N.P. Pakhorukov, V.N Sysa & Yu.V. Chmovzh 1989. Capture of Eels of Families Synaphobranchidae, Notacanthidae in the Western Part of Pacific Ocean. Biologiya Morya. 4 : 76–77 (In Russian).

Golovan G.A., N.P. Pakhorukov & V.N. Sysa 1990. Distribution and Behavior of Deepwater Fishes off Kuril Islands. Biologiya Morya. 1 : 70–72 (In Russian).

James, G.D., T. Inada & I. Nakamura 1988. Revision of the Oreosomatid Fishes (Family Oreosomatidae) from the Southern Oceans, with a Description of a New Species. New Zealand Journal of Zoology. 15(2) : 291–326.

Jonsson, G. 1976. Icelandic Observations on Rare Fish, 1974. Annales Biologiques, Copenhagen.31 : 180.

Jonsson, G., J.V. Magnusson & J. Magnusson 1977. Icelandic Observations on Rare Fish in 1975.Annales Biologiques, Copenhagen. 32 : 180–182.

Karrer, C. 1990. Oreosomtidae. P. 637–640. In: Quero, J.C., J.C. Hureau, C. Karrer, A.Post & L.Saldanha. (Eds). Check-list of the Fishes of the Eastern Tropical Atlantic (CLOFETA). Lisbon: JNICT, Paris: SEI, Paris: UNESCO. Vol. 2.

Kobayashi, K., M. Mikawa & J. Ito 1968. Descriptions of the Young and One Immature Adult Specimens of Coster Dory, Allocyttus verrucosus (Gilchrist) from the Northern Part of the Pacific. Bulletin of Faculty of Fisheries Hokkaido University. 19(1) : 1–5.

Lea, R.N. & R.H. Rosenblatt 1987. Occurrence of the Family Notacanthidae (Pisces) from Marine Waters of California. California Fish and Game. 73(1) : 51–53.

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Lyle, J.M. & D.C. Smith 1997. Abundance and Biology of Warty Oreo (Allocyttus verrucosus) and Spiky Oreo (Neocyttus rhombodalis) (Oreosomatidae) off South-eastern Australia. Marine and Freshwater Research. 42(2) : 91–102.

Lyle, J., Riley, S., & J. Kitchener 1992. Oreos - an Under-utilized Resource. Australian Fisheries 52(4): 12–15.

Maruyama, K. 1970. Some Deep-water Fishes from off the Tohoku and Adjacent Regions. Bulletin of Tohoku Regional Fisheries Research Laboratory. 30 : 43–66.

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Melnikov, Yu.S. 1981. Size-age Composition and Growth Peculiarities of Coster Dory Allocyttus verrucosus (Gilchrist) (Oreosomatidae). Voprosy Ikhtiologii. 21(2) : 380–385 (In Russian).

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Paxton, J.R., D.F. Hoese, G.R. Allen & J.E. Hanley 1989. Pisces. Petromyzontidae to Carangidae.Zoological Catalog of Australia. Vol. 7. Canberra: Australian Government Publishing Service, 665 pp.

Peden, A.E. 1976. First Records of the Notacanth Fish, Notacanthus chemnitzi Bloch, from the Northeastern Pacific. California Fish and Game. 62(4) : 304–305.

Quero, J.C., M.H Du Buit & J.J. Vayne 1997. Les Captures de Poissons àAffinités Tropicales lelong des Côtes Atlantiques Européennes. Annales de la Sociétédes Sciences Naturelles de la Charente-Maritime. 8(6) : 651–673.

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Seasonality in fish community and population structure on the continental slope of the Western Mediterranean

J. Moranta1, M. Palmer1, E. Massutí2, B. Morales-Nin1 and C. Stefanescu3
1 CSIC-UIB IMEDEA Institut Mediterrani d'Estudis Avançats
Miquel Marqués 21, 07190 Esporles, Spain
<joan.moranta@uib.es>

2 IEO Centre Oceanogràfic de les Balears
P.O. Box 291, 07080 Palma de Mallorca, Spain

3 Museu de Granollers -Ciències Naturals
Francesc Macià 51, 08400 Granollers, Spain

The concept of temporal stability in the deep-sea is valid for much of the world oceans and over mesoscale terms. However, this presumed stability is only apparent as periodic variability occurs in certain areas more frequently than originally supposed. Seasonal changes in the spatial structure of several deep-sea faunal groups have been described in the western Mediterranean, even when this area is characterized by a high degree of environmental stability below a depth of 200 m. This contribution analysed seasonality in Mediterranean deep-sea fish assemblages by comparing species composition, ecological parameters, biomass spectra and length frequency distributions of the main species. The data were collected in the Algerian (AB) and Balearic (BB) Basins, in the southern and northern part of the Balearic Islands, respectively. These two areas are characterized by different oceanographic conditions and are connected by a series of sills between depths of 100 to 800 m and which play an important role in the general circulation and the transport of water masses between them. The Balearic basin is characterised by the presence of numerous submarine canyons, which can also influence the environmental conditions in this area. In the AB 38 trawls were taken along a continuous transect at 400 and 1714 m depth (26 in autumn and 12 in spring'). In the BB 36 bottom trawls were carried out between 350 and 1300 m depth at three different sampling locations. Three samples were taken at each station on four surveys carried out in spring, autumn, winter and summer.

The two surveys made in the AB, where the number of hauls by season and depth strata was different, and the bathymetric range prospected large, was analyzed by means of a partial-detrended Canonical Correspondence Analysis (CCA) to test between-cruise differences on species composition, both for standardised number of individuals and biomass. A partial CCA was performed in the case of the four surveys made in the BB examining the same number of hauls by season and depth strata over a restricted bathymetric range. Assuming that species turnover in a bathymetric range is determined mainly by the depth, we focus on the analysis on the season-depth interaction and evaluated if the species composition and the abundance-biomass profiles follow the same seasonal pattern in all three depth strata.

Depth is the most important feature affecting the turnover in the species composition and the community structure in both the Balearic and Algerian Basins. The habitat topography, in this case the presence of a submarine canyon, is another factor which determines the segregation between the samples of the upper slope. In addition, the ecological parameters, the normalised biomass spectra and the size of some dominant species are also characterised by seasonal variations. Thus, seasonality is another factor that determines the substitution of the relative importance of some dominant species, but mainly for species with a minor contribution. The species composition and the abundance-biomass profiles follow different seasonal patterns in all three depth strata but with a minor variability at greater depths. Seasonality characterises distinct normalised biomass spectra (nBS) and plays a different role in the upper and lower assemblages. A pronounced seasonal change in nBS takes place on the fish assemblages shallower than 800 m depth, while the temporal change is comparatively smaller at greater depths. Seasonal changes in deep-sea fauna seem to be linked to the influence of submarine canyons in transporting sediments rich in organic matter and changes in the density and the biological cycle of the Benthic Boundary Layer macrofauna, which constitute an important part of the available food exploited by megafauna.

NORFANZ biodiversity survey uncovers mysteries of the deep

M.R. Clark1 and C. Roberts2
1 National Institute of Water and Atmospheric Research
P.O. Box 14–901, Wellington, New Zealand
<m.clark@niwa.co.nz>

2 National Museum of New Zealand Te Papa , Tongarewa
Wellington, New Zealand

A survey of the biodiversity of fishes and benthic invertebrates was carried out on the Lord Howe Rise and Norfolk Ridge in May–June 2003. The principal objectives of the “NORFANZ”programme was to survey, sample and document the marine biodiversity from seamounts and slopes on the Norfolk Ridge and Lord Howe Rise, to support biosystematics research projects, to assess the faunal uniqueness and conservation value, and to relate observed distribution patterns with measured biological and physical parameters.

An international team of scientists was involved in the four-week survey which was done using the NIWA research vessel, the R.V. Tangaroa. Fourteen seamount and slope sites were sampled, ten on the Norfolk Ridge, and four on the Lord Howe Rise. A total of 168 stations were completed, consisting of 144 trawl-sled-dredge shots, 15 casts to measure oceanographic conditions and nine camera drops to photograph fauna on the seafloor. Trawl depths ranged from less than 100 m to over 2000 m. A variety of gears were used, including bottom trawls, a midwater trawl, beam trawl, epibenthic sleds and rock and pipe dredges.

Over 500 fish species and 1300 macro-invertebrate species were provisionally identified onboard. This is regarded as a minimum estimate of the biodiversity, as the sampling intensity on individual seamounts was not sufficient to measure the complete faunal composition. About 20 percent of the fish species are likely to be either new records for the region, or newly identified species. It may take researchers around the world several years to fully examine the material, especially the invertebrates, and describe the unknown species.

There were a number of special features of the survey that contributed to its success. There was a high level of collaboration and cooperation between the New Zealand and Australian funding agencies and all the scientific institutes and museums. The team of international scientists covered a wide range of skills and experience and this enabled much to be achieved during the survey. The variety of gear types deployed during the survey were able to sample different components of the fauna and will contribute to a better understanding of the structure of the benthic community. The multibeam system used by the R.V. Tangaroa enabled bathymetry and bottom type to be rapidly assessed and was a valuable aid to planning the trawling. Photographs were taken of every species caught and were used as a reference guide throughout the survey to ensure accuracy and consistency of species identifications. Overall, strong and productive synergies developed between scientists from various disciplines and this, coupled with the experience of the officers and crew, produced an excellent survey result.

On the diversity, population ecology and biogeography of myctophidae

R.M. Wienerroither1, F. Uiblein2, F. Bordes3, T. Moreno3, J.G. Nielsen4, T.Sutton5 and M.Youngbluth5
1 Institute of Zoology, University of Salzburg, Hellbrunnerstrasse 34, A-5020 Salzburg, Austria
<rupert.wienerroither@sbg.ac.at>

2 Institute of Marine Research, Bergen, Norway
3 Instituto Canario de Ciencias Marinas, Telde, Spain
4 Zoological Museum, University of Copenhagen, Denmark
5 Harbour Branch Oceanographic Institution, Fort Pierce, Florida, USA

1. INTRODUCTION

An overview of the PhD project of the first author within the framework of an international collaboration on lanternfish (Myctophidae) ecology is given. Mesopelagic fishes play an important trophic role in the open ocean as well as close to steep slopes. Myctophidae in particular display a high diversity that can be used as an indicator of biogeographic distinctness of a specific area. The life history and adaptive strategies at the level of individual populations of myctophid species are poorly documented. In order to integrate these various aspects, a comparative study has been initiated.

2. MATERIAL

The investigations are based on material of the global “DANA” deep-sea expedition that is deposited at the Zoological Museum, Copenhagen (ZMUC), and on collections from recent pelagic research cruises in deep-water canyons south of Georges' Bank (NW Atlantic), the Canary Islands (Eastern Central Atlantic) and the Gulf of Mexico.

3. DATA ANALYSES AND PERSPECTIVE

Data on species composition and spatial distribution of mesopelagic fishes collected off the Canary Islands shows that myctophids are distributed patchily at a rather small spatial scale (Wienerroither 2003). These distribution patterns are consistent with areas characterized by high productivity and specific hydrological phenomena like upwellings and eddies. MOCNESS-catches close to deep-water canyons on the southern edge of Georges' Bank (Wienerroither, Suiblein and Youngbluth 2003) enable an even more detailed analysis of the small-scale distribution of myctophid species. Populations of geographically separated areas will be compared using meristic and morphometric characters to reveal possible adaptations to ecologically different environments.

Commercially-targeted fishes as well as marine mammals and birds use myctophid species as important sources of food. Adequate and sustainable ecosystem management requires holistic consideration of the food web, with detailed knowledge about the lifecycle and population structure of its components. This necessity is reinforced but also complicated by the insight that geographically separated populations of the same mesopelagic fish species have differing life history data.

4. LITERATURE CITED

Wienerroither, R.M. 2003. Species composition of mesopelagic fishes in the area of the Canary Islands, Eastern Central Atlantic. Informes Técnicos del Instituto Canario de Ciencias Marinas, 9: 1–110.

Wienerroither, R.M., F. Uiblein & M. Youngbluth 2003. Species composition and distribution patterns of myctophids and associated midwater fishes in the Gulf of Maine, NW Atlantic. Report from the Nanomia research cruise, September 2002, 8 pp.

Spatial pattern of demersal fish in the upper continental slope off Northeast Atlantic in Moroccan waters

A. Faraj and H. Masski
Institut National de Recherche Halieutique (INRH)
2 rue Tiznit, 20200 Casablanca, Morocco
<faraj@inrh.org.ma> and <hmasski@inrh.org.ma>

1. INTRODUCTION

The upper continental slope off the Northeast Atlantic in Moroccan waters (21°–28°N) have been surveyed between 100 and 800 m. A total of 90 bottom trawl hauls allowed us to obtain and identify 156 species from 72 families of demersal and benthic macrofaunal fish. Relative ichthyofaunal biomass per bathymetric strata estimates confirms a decrease in biomass with increase in depth but only from the strata corresponding in depth 400–500 m onwards. Above this strata, from 100 to 400 m, the upper continental slope corresponds to the transition zone between the continental shelf and the continental slope ecosystems, in which occurred most of the 38 macrofaunal fish species that are both slope and shelf-dwellers. The limit around 400 m is characterized by the inversion of ichthyofaunal biomass, biodiversity indexes and species richness tends.

The objective of this study was first to complete the knowledge of the spatial pattern of demersal and benthic fish in this area. Second, it tries to show, in terms of relative biomass, species composition and biodiversity, the characteristics of this particular area of transition, which marks the beginning of the deep-sea ecosystem.

2. METHODS

Data for the present study were collected during the R.V. Fridtjof Nansen bottom-trawl survey (Cruise Reports, Dr Fridtjof Nansen 2000), which was carried out in October 2000 as part of a regional collaboration involving Norway, Morocco, Mauritania, Senegal and The Gambia. It undertook an exploration of the upper continental slope between 150 and 800 m. The results of this study concern only the Moroccan part, from 20°50' N to 28° N.

Ninety stations were trawled following a bathymetric-stratified sampling strategy (Figure 1). Each station was sampled for about half an hour by trawling, but all results have been standardized to a tow duration of one hour.

The depth strata were defined as follows:

S1: 100–200 m
S2: 200–300 m
S3: 300–400 m
S4: 400–500 m
S5: 500–600 m
S6: 600–700 m
S7: 700–800 m

Formulas used in estimating indices were as follows.

N = Species richness

Hill (1973) indexes

where s is species richness and pirelative abundance of the ith species.

where pi is the relative abundance of the ith species.

Shannon Index

where pi is the relative abundance of the ith species.

Evenness Index

Specie(s) Indicator Value for strata, j

IV j,s = FI j,s* SP j,s * 100

where

SP j,s

and,

FI j,s

(Dufrêne and Legendre 1997).

FIGURE 1
Global map: Survey area (100–800 m; 20°50'–28°), SST and total biomass catch of demersal fishes

FIGURE 1

3. RESULTS

One hundred and fifty-six species of macro fauna fish were identified from 72 families. The more important families are represented according to their relative catch proportions (Figure 2). The stations' specific richness varied from 6 to 26 species (Figure 3).

Among the most important species in terms of biomass catch, were Helicolinus dactylopterus (Sebastidae), Hoplostethus mediterraneus (Trachichthyidae), Capros aper (Caproidae) and Merluccius merluccius (Merlucciidae). We also found numerous species of Macrouridae including Hymenocephalus italicus, Trachyrincus scabrus and Nezumia aequalis. The three most diversified families found were the Rajidae represented by 11 species, the Dalatiidae represented by 11 species and the Macrouridae represented by nine species.

FIGURE 2
Relative biomass of macrofauna fish families in the upper continental slope
FIGURE 2
FIGURE 3
Distribution of species richness
FIGURE 3

The major result was the gradual evolution, from shallower to deeper water, of the species composition (established according to the relative importance index) per strata. This evolution was marked by a simultaneous and gradual decline of those species that are present either on the shelf and the slope, and a gradual increase of the species that are the deeper-strata dwellers (Table 1 and Figures 4 and 5). Figure 5 shows the indicator values of the most representative species of each stratum.

TABLE 1
Relative biomass of macrofaunal fish species per bathymetric strata (%)

SpeciesS1S2S3S4S5S6S7
Bathygadus melanobranchus------0.43
Capros aper52.6863.034.23----
Chaunax pictus-----0.97-
Chlorophtalmus atlanticus1.89------
Chlorophtalmus punctatus-----1.18-
Coelorinchus coelorinchus--0.040.22---
Cyttopsis roseus--0.01----
Deania calcea------4.54
Dentex macrophtalmus14.710.360.01----
Dentex maroccanus0.89------
Epigonus telescopus---0.411.881.481.12
Galleus polli--0.01----
Helicolenus dactylopterus25.2726.1719.0476.4140.971.07-
Hoplosthetus cadenati---0.482.955.565.16
Hoplosthetus mediterraneus-10.3676.6010.6224.5833.190.24
Hymenocephalus italicus---0.2710.8023.110.11
Lepidopus caudatus1.790.01-----
Macrorhamphosus scolopax1.380.03-----
Merluccius merluccius-0.020.048.243.00--
Merluccius polli---0.24---
Nezumia aequalis---0.355.1317.3439.71
Scorpaena elongata0.10------
Setarches guentheri---2.131.27--
Synagrops microlepis1.05------
Trachyrincus scabrus----8.2313.0541.76
Trachyscorpia cristulata echi-----0.856.26
Xenodermichthys copei------0.24
Zenopsis conchifer--0.01----
Zeus faber0.09------
Others0.160.01-0.620.792.190.44

FIGURE 4
Bathymetric ranges and indicator value results for the 156 macro faunal fish

A0337E47.jpg (256323 bytes)

The biodiversity indexes (Gray 2000) computed at different scales [point scale, bathymetric strata scale (α-diversity) (Whittaker 1960) and inter-bathymetric strata scale (β-diversity)] showed a faunal break line around a depth of 400 m (Figure 6). An inversion of both point diversity and α-diversity index trends occurred after S4 strata (400 to 500 m). The maximum of the β-diversity occurred between the S3 and S4 strata and the minimum was observed between the S4 and S5 strata. There is also an inversion of the total demersal fish biomass (mean catch) trend with increasing depth.

FIGURE 5
Indicator value results of the most representative species for each stratum

StrataFamilySpeciesIVs
S1
100–200
TRANCHINIDAETrachinus vipera55
ZEIDAEZeus faber51
SPARIDAEDentex maroccanus50
S2
200–300
CAPROIDAE  
SCYLIORHINIDAECapros aper52
SPARIDAEScyliorhinus stellaris28
  Dentex macrophthalmus26
S3
300–400
TRACHICHTHYIDAEHoplostethus mediterraneus48
ZEIDAECyttopsis roseus36
MACROURIDAECoelorinchus coelorhincus27
S4
400–500
MERLUCCIIDAEMerluccius merluccius48
ZEIDAEZenopsis conchifer28
MERLUCCIIDAEMerluvvius polli26
S5
500–600
MACROURIDAEHymenocephalus italicus36
S6
600–700
MACROURIDAEHymenocephalus italicus28
SEBASTIDAETrachyscorpia capensis26
S7
700–800
MACROURIDAEBathygadus melanobranchus45
SEBASTIDAETrachyscorpia cristulata Echi29
RAJIDAERaja alba27

FIGURE 6
Biodiversity trends per strata
FIGURE 6
FIGURE 6

5. LITERATURE CITED

Cruise Reports Dr Fridtjof Nansen 2000. Survey of the demersal fish resources off North West Africa October 2000.

Dufrêne, M. & P. Legendre 1997. Species assemblages and indicator species: the need for a flexible asymmetrical approach. Ecol. Monogr.67, 345–366.

Gray, J.S. 2000. The measurement of marine species diversity, with an application to the benthic fauna of the Norwegian continental shelf. J. Exp. Mar. Biol. Ecol. 250, 23–49.

Hill, M.O. 1973. Diversity and evenness: a unifying notation and its consequences. Ecology 54, 427–432.

Whittaker, R.H. 1960. Vegetation of the Siskiyou Mountains. Oregon and California. Ecol. Monogr. 30, 279–338.

Seamount fishes -species composition on seamounts and adjacent slope

Dianne Tracey, B. Bull, M. Clark and K. Mackay
National Institute of Water and Atmospheric Research Ltd (NIWA)
P.O. Box 14901, Wellington, New Zealand
<d.tracey@niwa.co.nz> <m.clark@niwa.co.nz> <k.mackay@niwa.co.nz> and <brian@datamine.co.nz>

Seamount features are prominent in the New Zealand marine environment and provide an important habitat for deepwater fish such as orange roughy, smooth oreo, black oreo, and black cardinalfish.

Research trawl and acoustic surveys have been regularly carried out in several areas around New Zealand and, while primarily monitoring the change in relative abundance of the major deepwater commercial species over time, information on the composition of fish assemblages on seamounts and the adjacent slope area has also been reported. These surveys provide an opportunity to compare and examine such variables as species dominance, diversity, fish density and faunal rarity. In addition, data from these surveys have enabled an examination in trends in abundance between the seamounts and between the seamounts and neighbouring flat area (Figure 1).

FIGURE 1
New Zealand regions included in the study. Seamount complexes are indicated by black dots and adjoining slope areas by pale rectangles

FIGURE 1

In this paper we report on species dominance on the Northwest Chatham Rise (“Graveyard seamounts”) and show how the species composition on theses seamounts differs from that of the neighbouring slope area. The top 20 species caught were ranked by weight. Log catch rates and percentage occurrence for the top 10 species for the seamount complex and neighbouring slope are presented in Figure 2. The catch rates and percentage occurrence of orange roughy was high followed by a steep decline to the occurrence levels of other species. In the flat slope area, while orange roughy was still the dominant species, a less dramatic decline of catch rate and occurrence is displayed (top graph, Figure 2).

FIGURE 2
Catch rate on the log scale (left-axis) and percentage occurrence (right axis) for the ten species with the highest catch rate in the Northwest Chatham Rise area

FIGURE 2

We also examined species variation within a seamount complex. A descriptive analysis of species composition for six seamounts in the Southeast Chatham Rise “Andes Complex area was described. Of the 36 species recorded, five (13%) were caught on every seamount, a further 18 (50%) occurred on three to five seamounts, and six (16%) ‘rarer’ species occurred on only one seamount.

The mean species richness at each seamount complex in the New Zealand region was estimated and a trend with latitude was evident, with southern areas having higher mean species richness (Figure 3).

FIGURE 3
Relationship between latitude and mean species richness on seamount complexes

This work was funded by the Foundation for Research, Science, and Technology (Project COIX0028) and is based on a paper by the authors published in 2004.

FIGURE 3

Peruvian deep ocean potential resources: fishes and shrimps

A. Kameya, M. Romero and S. Zacarías
Instituto del Mar del Perú (IMARPE)
P.O. Box 22, Callao, Perú
<akameya@imarpe.gob.pe> <mromero@imarpe.gob.pe> <sheila_z@hotmail.com>

1. INTRODUCTION

In Peru a priority is to identify new species as potential resources to satisfy the national and international demand for fish, to create employment opportunities for the Peruvian community, to stimulate fishing investment and try to provide a fishing alternative when there is a decrease, for whatever reasons (overexploitation or by natural events), in abundance of fisheries resources. While earlier studies have been done (e.g. Del Soar and Alamo 1970, Del Soar and Mistakides 1971a, b, Del Soar and Flores 1972, Kameya et al. 1997)) it was clear that further work was needed and hence a number of cruises were undertaken to identify new species as potential resources to satisfy national and international demand for fish.

2. MATERIALS AND METHODS

Information was obtained during the cruises to identify potential fishery resources. These cruises were carried out using several different vessels. The fish caught were identified as to their species and their size and weight distributions were measured to determine if any of them might be potential fishery resources. A Granton-type net trawl, bottom long-lines and traps were used for sampling. The studied area was between 3° 30' – 18° 7' in a depth range of 201–1500 m.

The cruises to survey potential resources in the waters of Peru were carried out on board of the Research vessels Antum Brum (1966), Kaiyo Maru (1968), Challwa Japic № 1 (1971), SNP-1 (1970–1972), Chatyr-Dag in 1971, Wiracocha in 1971 (Vilchez, Del Soar and Viacava 1971), Kinca (1985), Fridtjof Nansen in 1990 (Veles et al. 1992), BIC Humboltd (1996), R.V. Nova Peru (1997), R.V. Moresko (1997) and R.V. Shinkai Maru in 1998, 1999 and 2000 (Chipollini et al. 1999, Zeballos et al. 2001).

3. RESULTS

During the cruises mentioned above about 150 species were identified. The most important potential resources found were: deep red shrimps (7 species) including (Haliporoides diomedeae), Chilean knife shrimps (Solenocera agassizii), colibrí shrimp (Nematocarcinus agassizzi), spider shrimp (Heterocarpus vicarius), northern nylon shrimp (Heterocarpus hostilis), Panama nylon shrimp, deep-sea crab species (Paralithodes camtschaticus) and king crab (10 species): Lithodes panamensis, Lithodes wiracocha, Paralomis inca, Paralomis longipes, Neolithodes spp. This last species was encountered as bycatch in the Dissotichus eleginoides fishery. More than 20 species of fishes were encountered including Roulenia spp., Alopocephalus tenebrosus, Macrouridae (ratfishes), orange roughy (Hoplostethus pacificus), black brotula (Cherublemman emmelas), snake eels (Ophichthidae spp.) and whiteface hagfish (Myxine circifrons). All of these species are in strong demand on international markets. Further details are provied by Zeballos et al. (1999).

4. CONCLUSIONS

The conservation of the deep oceans’diversity requires effort to maintain its productivity and ensure sustainable development, especially considering that deep colonizers are slow growing species.

Three phases are necessary to develop a fishery for these resources: (a) exploration, (b)application and (c), fishery developing. At the same time, it is necessary to carry out further operations to obtain the scientific knowledge for the conservation of species and to develop and sustain the local fishing economy to increase economic and social benefits (Del Solar 1987).

It is important to consider at the beginning of the search the risk of over exploration in any new fishery and to understand the effects of this fishery on the ecosystems, i.e. their ecological integrity, diversity and productivity.

5. LITERATURE CITED

Chipollini, A., L. Velazco, Y. Hooker, W. García, J. Wasiw & J. Calderón 1999. Crucero de Investigación de recursos demersales y potenciales R.V. Shinkai Maru 9907-08. Instituto del Mar del Perú. Informe Ejecutivo.

Del Solar, E. 1987. Recursos de la zona arquibentónica peruana. Boletín de Lima, 50:77–85.

Del Solar, E. & V. Alamo 1970. Exploración sobre distribución de langostinos y otros crustáceos de la zona norte. Crucero SNP-1 7009 (1era.Parte) Instituto del Mar del Perú. Serie Informes Especiales. IM-70: 18pp.

Del Solar, E. & L. Flores 1972. Exploraciones de crustáceos (zona sur ), crucero SNP 1-7201. Instituto del Mar del Perú. Serie de Informes Especiales. IM-107: 8pp.

Del Solar, E. & M. Mistakides 1971a. Informe del crucero SNP-1 7105. Exploración de crustáceos. Instituto del Mar del Perú. Serie de Informes Especiales. IM-70: 18pp.

Del Solar E. & M. Mistakides 1971b. Informe del crucero SNP-71. Informe del crucero SNP-7105. Exploración de crustáceos. Instituto del Mar del Perú. Serie de Informes Especiales. IM-89: 10pp.

Kameya, A., R. Castillo, L. Escudero, E. Tello, V. Blaskovic, J. Cordova, Y. Hooker, M. Gutierrez & S. Mayor 1997. Localización, distribución y concentración de los langostinos rojos de profundidad. Crucero BIC Humboldt 9607-08 (18 de julio a 06 de agosto de 1996). Publicación Especial, Instituto del Mar del Perú: 52pp.

Velez, J., A. Kameya, C. Yamashiro, N. Lostaunau & O. Valientte 1992. Investigación del Recurso Potencial lanogostino Rojo de Profundidad a bordo del BIC Fridtjof Nansen (25 de abril – 25de mayo 1990). Instituto del Mar del Perú. Informe № 4: 1–24.

Vilchez, R., E. Del Solar & M. Viacava. 1971. Informe de crucero 7011 (3ra.parte) y 7101. Instituto del Mar del Perú. Serie de Informes Especiales, IM-78: 1–14.

Zeballos, J., W. García, W. Castañeda, I. Velazco, J. Wasiw & Y. Hooker1999. Resultados Generales del Crucero de Investigación de los Recursos Demersales y Potenciales y su Relación con las condiciones ambientales del Fenómenos El Niño 1997–98. Instituto del Mar del Perú. Informe Ejecutivo (1998).

Zeballos, J., M. Romero, W. García, A. Aliaga, J. Wasiw & S. Peraltía 2001. Crucero de Investigación de Recursos de Demersales y Potenciales R.V. Shinkai Maru 2000-04-05. Instituto del Mar del Perú. Informe Ejecutivo (2000).

The deep ocean biodiversity of the Peruvian sea: fishes and invertebrates -Peruvian activities

A. Kameya, M. Romero and S. Zacarías
Instituto del Mar del Peru (IMARPE)
P.O. Box 22, Callao, Perú
<akameya@imarpe.gob.pe> <mromero@imarpe.gob.pe> <sheila_z@hotmail.com>

1. INTRODUCTION

Peru is considered to have mega-ecological biodiversity; however, the biodiversity of its marine ecosystem has received little attention up to now compared with its terrestrial environments. In spite of the Peruvian coast line being more than 3000 km in length, the amount of knowledge and conservation of the marine ecosystem are scarce compared with those of the terrestrial environments. It is necessary to focus on the marine biological diversity processes and their enormous potential, not only as a sources of proteins but also as source of a great variety of active principles for industrial applications and medicine.

More recent studies have given scientists plenty of scope to argue that the ocean bottom supports as diverse habitats as any community on Earth. Therefore, since 1970 IMARPE has been researching the biodiversity of these marvelous bottom ecosystems.

2. PROGRAMME OBJECTIVES

To research the distribution, concentration and abundance of the Peruvian deep marine biodiversity, focusing mainly on fishes and invertebrates, to plan their management and conservation as well as contribute with information to the Convention of Biological Diversity.

3. MATERIAL AND METHODS

Information was obtained from three cruises carried out on board at the BIC Shinkai Maru during 1998, 1999 and 2000 (Chipollini et al. 1999, Zeballos et al. 2000). The surveyed areas were between 3° 30' to 11° 00' S. The trawls were undertaken in the depth range of 201 m to depths exceeding 1 500 m.

According to procedures established in previous cruises, the acoustic tracks were determined by means of a random stratified sampling design. The detection of fish schools was used to recognize suitable zones for bottom trawling. The main oceanography characteristics in these zones were recorded. The following papers were used in this regard: Fitch and Lavenber (1968), Chirchigno and Velez (1998), Chirchigno and Cornejo (2001) and Méndez (1981).

4. RESULTS

In the analyses of the results, 247 species of fishes and 284 species of invertebrates were identified (Chirichigno and Vélez 1998). During the three cruises, fishes were found to be the dominant group (94–96.6 percent) including Merluccius gayi peruanus, Roulenia sp., Cherublemma emmelas. Those of Alepocephalus tenebrosus, Hoplostethus pacíficus, and Dicrolene filamentosa were the dominant species. Regarding invertebrates, the deep-sea red shrimp Haliporoides diomedeae was the dominant species in 1998, 1999 and 2000 (Zeballos et al. 1998).

The fishes Merluccius gayi peruanus and Cheurublemma emmelas were the species most frequently found in Stratum I (200–500 m). Other species found were Physiculus talarae, Ophichthus tetratema, Gnathohis cintus, Pontinus furcirhinus, and Peristedion spp. but these were not observed in the other zones.

The degree of species of diversity was associated with the depth. It was highest as the depth increased with the highest diversity registered in stratum II (500–1000 m 5.4–5.5bits), the diversity value then decreased in stratum III (1 000–1 500 m). Oceanographic parameter mean values observed between 500–1000 m deep were: temperature 4.5–8.5°C, salinity 34.5–34.65 ups and oxygen, 0.5–1.5 ml/l.

The following species were frequently found in stratum II (500–1000 m): Hoplostethuspacíficus, Coryphaenoides delsolari, Coelorinchus canus, Rajas spp., Xenomystax rictus, Apristurus nasutus, Hydrolagus macrophthalmus, Trachyrinchushelolepis, Rhinochimaera pacifica and Alepocephalus tenebrosus.

In stratum III (1 000–1 500 m), Alepocephalus tenebrosus was the dominant species, Roulenia sp. and Dicrolene filamentosa were observed but were much less frequent than the main species.

5. CONCLUSIONS

6. LITERATURE CITED

Chirichigno, N. & J. Vélez 1998. Clave para identificar los peces marinos del Perú (Segunda Edición. Revisada y actualizada). Pub. Esp. Instituto del Mar del Perú. 500 pp.

Chirichigno N. & M. Cornejo 2001. Catálogo Comentado de los Peces Marinos del Perú. Instituto del Mar del Perú. Publicación Especial: 1–314.

Chipollini, A., L. Velazco, Y. Hooker, W. García, J. Wasiw & J. Calderón 1999. Crucero de Investigación de recursos demersales y potenciales R/V Shinkai Maru 9907–08. Instituto del Mar del Perú. Informe Ejecutivo.

Fitch J.E. & J. Lavenber 1968. Deep-water Fishes of California. Univ. California Press. London, England. 150 pp.

Zeballos, J., W. García, I. Castañeda, L. Velazco, J. Wasiw & Y. Hooker 1998. Resultados Generales del Crucero de Investigación de los Recursos Demersales y potenciales y su Relación con las condiciones ambientales del Fenómenos El niño 1997–98. Instituto del Mar del Perú. Informe Ejecutivo.

Zeballos, J., M. Romero, W. García, A. Aliaga., J. Wasiw & S. Peraltía 2000. Crucero de Investigación de Recursos de Demersles y Potenciales R/V Shinkai Maru 2000–04–05. Instituto del Mar del Perú. Informe Ejecutivo.

Mendéz, M. 1981. Clave de Identificación y Distribución de los langostinos y camarones (Crustáceos: Decápodos) del Mar y Ríos del la Costa del Perú.Instituto del Mar del Perú. Boletín 5: 1–170.

The biology of deep-sea fishes: A review for the Mediterranean

J. Moranta1, E. Massutí2, B. Morales-Nin1 and C. Stefanescu3
1 CSIC-UIB IMEDEA Institut Mediterrani d'Estudis Avançats
Miquel Marqués 21, 07190 Esporles, Spain
<joan.moranta@uib.es>

2 IEO Centre Oceanogràfic de les Balears
P.O. Box 291, 07080 Palma de Mallorca, Spain

3 Museu de Granollers - Ciències Naturals
Francesc Macià 51, 08400 Granollers, Spain

The knowledge of the Mediterranean deep sea has increased progressively over the last few decades. Improvements in technology have allowed the bathymetric ranges that have been investigated to be expanded and thus enlarge the understanding of its deep-sea ecosystems and the biology of the most important species. A total of 84 fish species have been collected from bottom trawl deep-sea surveys carried out in the western Mediterranean. Some aspects of the biology of twenty demersal fish species (1Scyliorhinidae, 2 Squalidae, 1 Alepocephalidae, 1 Clorophthalmidae, 2 Notacanthidae, 7 Macrouridae, 2 Gadidae, 2 Moridae, 1 Trachichthydae and 1 Scorpaenidae), which represent more than 90 percent of abundance in terms of biomass, have been analysed, following a standardized format. This included whenever possible (a) distribution, (b) depth range, (c) length range, (d) sex composition, (e) longevity, (f) von Bertalanffy growth parameters, (g) morphometric relationships for Macrouridae species (HL-PAL relationships), (h) spawning season and type of spawn, (i) size of first maturity or smallest fish mature, (j) recruitment (season and depth) and, (k) diet. This biological information is complemented with research related to (a) depth-size trends, (b) population structure and differences in size between Mediterranean and Atlantic populations, (c) fecundity, (d) exploitation aspects and, (e) biological aspects to be studied in the future.

The data used came from two bottom trawl surveys undertaken during the spring and autumn off the Balearic Islands (Western Mediterranean) and from available biological studies on these species developed in the same, or adjacent, areas. The current knowledge of the biology of deep-water species in the Mediterranean is still fragmentary, especially in aspects related to the age composition, growth, reproductive characteristics and fecundity. However, we can conclude that species with different life histories are segregated by depth. Large fish, with high energy requirements are found mainly on the upper and middle slope while the more sedentary and, or, smaller species with low energy costs seem to be better adapted to the poorer environment of the lower slope.

In the context of r-k selection theory, some common patterns, such as slow growth, longevity, long life span and delayed maturity, show the deep-sea ichthyofauna to be k-strategists. These bio-ecological traits should be considered when establishing management policies for the regulation of any possible expansion of the Mediterranean deep-sea decapod crustacean trawl fisheries. Such considerations would be relevant in reducing the impact upon the fragile ecosystem of the Mediterranean deep sea by such fisheries.


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