(editors), Proc. 6th Annu. Meet. World Mariculture Soc, 

 p. 285-298. 



MITCIIKI.I,. J. R. 



1975. A polyculture system for commercially important 

 marine species with special reference to the lobster. 

 Honuiriisaiueritaruis. In J. W Avault, Jr., and R. Miller 

 (editors). Proc. 6th Annu. Meet. World Mariculture Soc. 

 p. 249-259. 



MOKIN'C;, J. R., .AM) K. A. MOKINC. 



1975. Succession of net biofouling material and its role in 

 the diet of pen-cultured chinook salmon. Prog. Fish- 

 Cult. 37(l):27-30. 



PRE.NTRK, E. F. 



1975. Spot prawn culture: status and potential. /« C. W. 

 Nyegaard i editor). Proceedings of a seminar on shellfish 

 farming in Puget Sound, Oct. 7, 1975, Poulsbo, Wash., p. 

 1-11. Wash. State Univ., Coll. Agric, Coop. Ext. Serv., 

 Pullman. 



RKN.SKI., J. E., .^\\^ E. F. PKKNPKK. 



1977. First record of a second mating and spawning of the 

 spot prawn, Pandalus platycerox, in captivity. Fish. 

 Bull., U.S. 75:648-649. 



WlCKl.WS, J, F. 



1972. Experiments on the culture of the spot prawn Pan- 

 dalus platyccros Brandt and the giant freshwater prawn 

 Macrobrachium roscnhcrgti ide Man). Fish. Invest., 

 Minist. Agric, Fish. Food (G.B.)., Ser. II, 27(5), 23 p. 



John E. Rk.wskl 



Squaxin Island Tribe 

 Route 1 , Box 25 7 

 She! ton. WA 98584 



E.AKl, F. PKKNTKK 



Northwest and Alaska Fisheries Center 

 National Marine Fisheries Service, NOAA 

 2725 Montlake Boulevard East 

 Seattle, W A 98112 



LARVAL LENGTH-WEIGHT RELATIONS FOR 



SEVEN SPECIES OF NORTHVC EST ATLANTIC 



FISHES REARED IN THE LABORATORY 



Growth is an important connecting link in the 

 functional influence of biotic and abiotic factors on 

 the dynamics of fish populations. Length-weight 

 relations are used by fishery scientists to describe 

 the growth characteristics of species or popula- 

 tions and as a basis of evaluating the consequences 

 of environmental influences on growth. Length- 

 weight relations are also used in assessing produc- 

 tion when combined with age and growth informa- 

 tion and in determining length or weight in a 

 situation where either one or the other is unknown 

 due to sampling procedures. 



Studies of the early life of fishes are receiving 

 increasing emphasis, particularly with regard to 



growth and survival in the larval stage. Survival 

 during this period is thought to be minimal and 

 potentially variable from year to year. Small 

 changes of tenths of a percent in mortality have 

 the potential to produce orders of magnitude dif- 

 ferences in eventual adult populations. Larval 

 growth can be influenced due to food limitations 

 and varying abiotic factors (Houde 1974; Lasker 

 1975; Laurence 1977). Because of these facts, 

 fishery scientists are particularly concerned with 

 two aspects: 1 ) quantifying variable larval growth 

 and survival, relating it to subsequent year-class 

 recruitment, and applying it to traditional stock- 

 recruitment relationships where recruitment has 

 often been considered constant; and 2) the poten- 

 tial use of this type of information in evaluating 

 the increasing effects of pollution or other en- 

 vironmental perturbations because of the fragility 

 and sensitivity of larvae to changing or altered 

 environmental variables. 



Solutions to these problem areas require quan- 

 titative knowledge of growth parameters of larval 

 fishes, and length-weight relations can be helpful 

 in providing information or establishing relation- 

 ships between pertinent sets of data. It is gener- 

 ally thought that weight' is a better measure of 

 absolute growth offish larvae than length as well 

 as the prime determinant of condition when com- 

 bined with length. Many species exhibit allo- 

 melric or dispi'oportionate length-weight growth. 

 This is especially true during the period of 

 metamorphosis when some species display vary- 

 ing or unusual body proportions with age (Blaxter 

 1969) and length does not increase in proportion to 

 increasing weight. Additionally, recent attempts 

 to construct models of larval survival, as 

 influenced by environmental variables and den- 

 sity dependent feeding relationships, require 

 weight detei'minations for estimates of biomass 

 and caloric tui-nover between larval and prey 

 trophic levels. 



There is an extensive data base to asses larval 

 fish growth and survival based on ichthyoplank- 

 ton collected on survey cruises during the last 75 

 yr by marine laboratories throughout the world. 

 Unfortunately, almost all of these data are in 

 standard or total length measurements as they are 

 much more easily and rapidly taken than dry 

 weights. The difficulty involved in obtaining dry 



'Weight for species in this research refers to dry weight. Dry 

 weight is the most accurate for fish larvae because accurate wet 

 weights are difficult to obtain and yield variable results on or- 

 ganisms as small as fish larvae. 



890 



FISHKKV Bl'I.I.KTlN Vol. 7fi. NO 4. 1979. 



