PRELIMINARY REPORT ON THE FISHERY AND BIOLOGY OF THE CHISENSE COMPLEX (POECILOTHRISSA MOERUENSIS, NEOBOLA MOERUENSIS) OF LAKE MWERU-LUAPULA (ZAMBIA) INCLUDING NOTES ON THE FEEDING OF THE SPECIES OF THE BY-CATCH (Contd.)

Table 2. Contents of the stomachs of Poecilothrissa moeruensis from various areas in Lake Mweru and the Luapula River. %V = percentage volume of that food category to the total volume of food within all stomachs examined. %N = percentage of individuals having that food item within their stomachs.

	All Samples		Luapula River		Lake >34 mm		Kenani		Isokwe Offshore		Isokwe Inshore
	N = 179		37		34		51		33		55
% Stomach Empty mean fullness of those	40.2		5.4		47.1		39.2		31.0		58.2
Stomachs with contents (%)	34.2		53.2		34.4		41.3		23.8		20.7
Mean fullness of all stomachs (%)	57.2		56.1		61.6		67.2		50.6		49.6
	%V	%N	%V	%N	%V	%N	%V	%N	%V	%N	%V	%N
ANIMAL: Diptera Larvae	37.0	31.3	8.4	21.6	54.1	41.2	66.8	56.9	48.1	27.3	26.3	18.2
Insect Remains (Adults)	29.7	25.1	61.2	86.5	16.2	8.8	2.2	3.9	28.4	15.2	23.9	10.9
Ephemeroptera Adults	6.3	10.6	17.5	45.9	1.7	2.9	-	-	2.5	6.1	-	-
Hemiptera Adults	1.3	2.8	0.9	8.1	5.1	2.9	-	-	-	3.0	5.2	1.8
Mollusca	0.2	1.7	-	-	1.1	5.9	0.6	3.9	-	3.0	-	-
Prawns	0.9	1.7	2.6	25.4	-	-	-	-	-	3.0	-	-
Eggs (Copepods)	0.7	1.7	-	-	3.0	2.9	1.6	2.0	-	3.0	0.9	1.8
Fishscales	0.1	1.1	-	-	0.4	2.9	0.2	2.0	-	3.0	-	-
PLANT MATTER: Algae	1.8	2.8	-	-	-	-	5.3	7.8	-	3.0	-	-
Plant fragments	1.6	3.9	4.6	16.2	-	-	-	-	-	3.0	-	-
OTHER MATTER: Organic Matter	20.5	27.4	4.8	18.9	18.3	29.4	23.2	49.0	21.0	15.2	43.8	21.8
Avg. Standard Length + St. Dev.	43.5+3.3		39.8+3.4		33.5+4.5		34.6+5.8		+32.9+4.2

Table 3. Contents of the stomachs of various fish species in the by catch of “Chisense” from Lake Mweru. %V = percentage volume of that food category of the total volume of food within all stomachs of that species examined. %N = percentage of individuals having that food item within their stomachs.

	N. moeruensis		B. cf. radiatus		H. sp. “orange”		A. macropthalmus		S. macrocephalus		R. intermedius
	N = 116		49		27		14		12		48
% Stomach empty mean fullness of those stomachs	80.2		18.4		22.2		53.3		58.3		79.2
With contents (%)	34.5		10.0		53.8		93.3		34.0		36.0
Mean fullness of all stomachs (%)	6.6		1.8		41.9		40.0		14.2		7.5
	%V	%N	%V	%N	%V	%N	%V	%N	%V	%N	%V	%N
ANIMAL MATTER: Fish	-	-	-	-	2.6	3.7	25.0	14.3	88.2	33.3	91.6	18.8
Copepods	-	-	2.2	2.0	17.9	48.1	-	-	-	-	-	-
Eggs	-	-	2.2	2.0	5.8	48.1	-	-	-	-	-	-
Adult Hemiptera	-	-	-	-	1.8	7.4	1.8	7.1	11.8	8.3	-	-
Adult Ephemeroptera	2.6	0.9	-	-	0.5	7.4	23.2	14.3	-	-	-	-
Adult odonata	3.9	0.9	-	-	-	-	8.6	14.3	-	-	5.4	2.1
Chitinous Remains	92.1	16.4	3.3	4.1	1.8	7.4	12.5	14.3	-	-	-	-
Diptera Larvae	-	-	4.4	4.1	21.8	63.0	19.6	14.3	-	-	-	-
Mites	-	-	-	-	0.4	3.7	-	-	-	-	-	-
Molluscs	-	-	-	-	2.5	25.9	-	-	-	-	0.3	2.1
Unidentified matter of animal origin	1.3	0.9	44.4	8.2	0.4	7.4	3.6	7.1	-	-	-	-
PLANT MATTER:	-	-	-	-	3.2	18.5	5.7	7.1	-	-	-	-
Plant Fragments
Seeds	-	-	-	-	1.1	11.1	-	-	-	-	-	-
OTHER MATTER: Fine particulate organic matter	-	-	43.3	10.2	40.0	70.4	-	-	-	-	2.7	6.3
Sand	-	-	-	-	0.1	3.7	-	-	-	-	-	-

Table 4. Number of eggs found in ovaries of P. moeruensis

Standard Length (mm)	Ovary State	% Length Ovary of Body Length	Number of Eggs	Mean Diameter of Eggs (mm)
26	Active	32.5	1140	0.11
33	Active	42.2	1135	0.20
27	Ripe	55.6	872	0.33
30	Ripe	52.5	899	0.33
41	Ripe	57.6	872	0.33
42	Ripe	50.0	1051	0.33

Table 5. Chisense Fishery: number of boat and/or gear owners (male/female), boats, workers, engines and sails, age of the fishery (=boat and/or gear owner), fishing activity in weeks per month and months per year. Data from the Frame Survey Lake Mweru-Luapula, July-August 1992.

	NUMBER OF FISHERS			NUMBER OF					FISHING ACTIVITY
STRATUM	MALE	FEMALE	AGE	BOATS	ENGINES	SAILS	WORKERS	WORKERS/FISHER	WKS/MONTH	MNTH/YEAR
1	758	26	36 + 9	998	49	93	3435	4.4 + 3.2	2.2 + 0.6	8.2 + 3.7
2	307	17	38 + 10	544	88	23	1843	5.7 + 3.9	2.4 + 0.7	9.6 + 3.6
3	57	4	40 + 9	122	16	0	286	6.3 + 2.9	2.1 + 0.6	8.3 + 3.4
4	51	0	39 + 11	71	3	0	232	4.5 + 3.6	2.4 + 0.8	6.0 + 4.2
Total	1173	47	37 + 10	1735	156	116	5787	4.8 + 3.5 min = 0 max = 34	2.3 + 0.6	8.5 + 3.8

Table 6. Distribution of Chisense gear and gill-nets over Lake Mweru-Luapula

STRATUM	JAPAN NET	BOAT SEINE	MUTOBI	LIFT NET	TOTAL	GILL NET
1	789	116	22	0	927	2596
2	135	225	3	10	373	851
3	2	59	10	0	71	22
4	6	41¹	8	0	55	33
Total	932	441	43	10	1426

¹ Mostly beach seines

Table 7. Distribution of mesh sies over the Chisense gear of Mweru-Luapula

GEAR TYPE	MESHLES S	6mm	10mm
BOAT SEINE	315	124	2
JAPAN NET	872	60	0
MUTOBI	42	1	0
LIFT NET	5	4	1
TOTAL(%)	86.5	13.3	2.1

100% = 1426

Table 8. Distribution of mesh sizes of gill-nets owned by Chisense fishers

GILL NET MESH SIZE (mm)	25	37	50	63	76	89	102	114	127	140	152
NUMBER PERCENTAGE	4 0.1	34 1.0	264 7.5	1611 46.0	736 21.0	56 1.6	221 6.3	432 12.3	111 3.2	11 0.3	22 0.6

Table 9. Distribution of Chisense fishers by tribal background

STRATUM	BWILE	TABWA	SHILE	LUNDA	BEMBA	OTHER
1	483	70	36	60	74	61
2	19	21	62	98	81	43
3	0	2	5	38	11	5
4	0	0	0	37	10	4
Total	502	93	103	176	233	113

Fig. 1 Map of Lake Mweru-Luapula showing the strata where sampling was carried out.

Fig. 2 Length frequency of Poecilothrissa moeruensis from the Luapula River and Lake Mweru proper. In the lake, sampling sites were near Isokwe Island.

Fig 3. Distribution and migration of Chinese fishers over Lake Mweru-Luapula during the various periods of the year