In many fisheries involving at-sea processing, labor may pose a constraint on total production or landings of fish. This appears to be the case for the Northwest Atlantic sea scallop fishery. Kirkley and DuPaul (1993) found that total production was limited by manpower rather than by gear and vessel attributes in the scallop fishery. The fishery is highly labour intensive in that scallop meats are removed from the entire animal at sea. In fisheries involving some type of at-sea processing, it may be necessary to consider capacity and capacity utilization relative to labour utilization.

**Endnotes**

1. On page 29, Beverton and Holt state, “We use the term fishing power to denote the catching power of an individual vessel and this is measured as the ratio of the quantity caught by that vessel per unit fishing time to that by a vessel selected as a standard reference, fishing at the same time and place and using a standard gear...The fishing effort of a fleet we then define in units of 'total standard hours fishing/year and fishing intensity (f) as fishing effort per unit area'.”

2. Quasi-fixed inputs (factors) are inputs that are held fixed or constant at the observed level for some period but eventually adjust to an optimum over a longer time period. These inputs are held fixed because of difficulties in making ready adjustments over comparatively short time periods. The capital stock is the input most typically considered quasi-fixed. For example, vessel size is often difficult to adjust over a relatively limited period of time but given enough time, new vessels can be constructed or used vessels purchased on the second-hand market. Labor is sometimes considered quasi-fixed, depending on the circumstances.

3. This approach compares not the output level at which the
short-run and long-run average cost curves are tangent, but measures the cost
gap that exists when observed output differs from optimal (Morrison, 1985). This
dual CU measure contains information on the difference between the current
temporary (short-run) equilibrium and the long-run equilibrium in terms of the
implicit costs of divergence from long-run equilibrium. It is defined as
CU^{C} = C^{*}/C, where C is the firm's actual cost and
C^{*} is its shadow cost. The shadow cost C^{*} is defined as
the cost of the variable inputs plus the shadow cost of quasi-fixed input equal
to the shadow price of the quasi-fixed input multiplied by the quantity of its
stock.

4. MAGPs set targets to Member States. Compliance is left to each Member State, by subsidiary, where each Member State designs a scheme subject to the European Commission's approval (Concerted Action, 1997). A decision is then issued by the European Commission with regard to the Member State along the lines of the draft MAGP. Member States regulate both entry and exit. When entry and exit schemes insufficiently regulate effort, days-at-sea restrictions are needed. Holden (1994) provides a comprehensive discussion.

5. De Wilde and van Beek (1996) observe that fishing capacity of individual vessels in Denmark is expressed in six parameters: gross tonnage, length, width, depth, hold volume, and engine power. Increases in any of these parameters requires the consent of the Ministry of Fisheries. Conversion of vessel with an engine power of 368 kw to beam trawling is not allowed. In Belgium, fishing capacity is controlled by a vessel licensing system, which allows no increase in aggregate engine power and tonnage. A decommissioning scheme serves to stimulate capacity reduction as required by the MAGP. Vessels can be replaced by those of the same horse power and gross tonnage, or licenses can be joined for new building up to a maximum tonnage of 385 GT, an engine power of 883 kw, and a length of 38m.

6. Working within this framework, Salz (1996; pages 74-75) observes that fishing effort is in principle composed of two elements: size of fleet and its level of activity. The determinants of fleet are number of vessels, gross tonnage, engine power, gear used, and technological progress. The determinants of activity level are time at sea and time fishing, know-how of skipper and crew, and fishing area.

7. The European Commission is the executive arm of the European Union. In addition, the decommissioning is carried out by the reverse bid system (Dutch auction) where owners submit a bid to the government for removing a vessel from the fleet (anon, n.d.). At a given time, government selects the lowest valued vessel capacity units and offers the owner the option of decommission at the value offered. The owner then has to destroy the vessel before a certain date.

8. Egner, Pope, and Rodgers (1996; page 126) observe that investment in fishing capacity is constrained by a number of factors, including the requirement to hold a pressure stock license and the rules governing new and replacement vessels (i.e. 120% of capacity must be purchased to secure a license for a new vessel). In the UK, the 20% capacity penalty is reduced to 10% if the replacement vessel is the same size as the one leaving the fleet (de Wilde and van Beek (1996, pages 187-188)).

9. Everett (1997) reports that Dr. Andrew Palfreman, Department of Economics, University of Hull, United Kingdom, indicated vessel capacity units were transferable and could be converted into horsepower and/or vessel size. It was believed that in the Scottish whitefish fleet, VCUs were being converted into size (length * breadth) and in the pelagic fleet they were being converted into horsepower. It was queried whether the same measurement or formula should be used in different fishing methods such as trawling where horsepower was important in measuring fishing effort and in purse seining where it was not as important. Apparently, a loophole arose when authorities tried to impose one measure of capacity to widely varying fishing methods and the fishers exploited this compromise by converting the VCUs to the parameters that they know are the most effective in the fishing method they are using.

10. In the Netherlands, engine capacity as officially used in the MAGP is measured by Shipping Inspectorate, the Dutch Division of the Ministry of Transport, and is measured at the shaft of the main engine on test bed (Frost et al., 1995).

11. Gross registered tonnage typically gives a better statistical fit than does length.

12. One of the most widely applied measures is length overall, which is the overall length of the hull, excluding bowsprit, spars, extensions, etc., which are not part of the hull structure. Load water line, sometimes also referred to as length water line or design water line, is the length of the intersection of the hull with the water surface when floating normally. Length between perpendiculars, also referred to as registered length, is the length from the intersection of the forward face of the stem with the waterplane to the after face of the rudder post. Hamlin (1990) recommends load water line.

13. Leontief separability is required. Hall (1971) states, “In vintage production functions with constant returns, the basic theorem of capital aggregation establishes that a capital aggregate exists if and only if the marginal product of capital of age i at time t has the fixed ratio... to the marginal product of new capital at time t.” This is called Fisher aggregation. See Fisher (1965) and Hall (1971) for further discussion.

14. Squires and Huppert (1988; page 3) note that a relative measure of fishing power over a standard fishing time fails to account for the amount of time different vessels fish and the complex mix of fishing modes and strategies encountered in a multispecies fishery. The expected catch (in the statistical sense) per vessel, given resource abundance, is useful because license limitation restrains actual catches on average at best, but does not limit the maximum catch.

15. Gulland (1983) observed that catch is frequently distributed log normally, giving rise to the taking of logarithms.

16. Greene (1993) and Coelli (1995) provide recent comprehensive surveys.