nSHERY BLLLETTN: VOL. 76. NO. 4 



reported statistics', too low for the F.R.G.. Japan. 

 Poland, and United States, and too high for the 

 other countries. In fact, summing the national 

 total TAC's rather than the linear program esti- 

 mate-; • "'■ c • : - - r>- catch, when the former are limit- 

 ing. : " overall estimated catch, results in 

 an expe :atch of 575.000 t. only 68^ of 

 the TAG. The analogous expected total 

 cater, derived from 1971 bycatch ratios was 

 627.470 t. only 74'~c of the overall TAG. Bycatch 

 may be reduced through actions initiated by 

 fishing fleets or by regulations such as the closure 

 to bottom trawling by larger vessels in the south- 

 em New England. Middle Atlantic, and Georges 

 Bank areas IGNAF 1975' for 1975 and by the 

 similar closure on Georges Bank for 1976. The 

 reduction of the overall TAG to 650.000 t in 

 1976 IGXAF 1976 ' and 525.000 1 in 1977 > IGXAF 

 1977 1 was designed to reduce the bycatch problem. 



It should be noted, however, that despite the 

 above potential for change as well as the in- 

 a^T _ -lies of the rep>orting to IGXAF. which may 

 c:~ : -r -.ore than one directed fisherv" under a 

 mixed category-, there were other factors which 

 worked in the opposite direction. The first was the 

 inadequate recording of bycatch noted during in- 

 ternational inspections. Some of this was dis- 

 carded and not rep>orted. and some was apparently 

 utilized but not accurately reported on logbooks. 

 Both the lack of reporting and any underestimates 

 of bycatch can cause the bycatch ratios used in this 

 anal\-sis to be underestimated. 



In mixed species fisheries, bycatch mxist be con- 

 sidered in the allocation of quotas to species and to 

 elements of the fisherj- 'in this example the ele- 

 ments are countries, but under different cir- 

 cumstances they cotild be otherwise — e.g.. ports i. 

 Lack of attention to attendant bycatch may result 

 in an unexpected overhar\"est of selected species or 

 conversely the wastage of large quantities of pro- 

 tein depending on whether or not the directed 

 fishen.' ceased when a small amount of bycatch 

 had been taken. Linear programming pro%ides a 

 suitable technique for examing this problem. 



However, to have a refined analysis, accurate 

 statistics as to main species sought and the com- 

 position of the bycatch including discards must be 

 available. Lacking these, the inferences as in this 

 pap>er. are directional. The specific indi\-idual es- 

 timates can be interpreted for policy decisions only 

 when the user has the understanding of the fishen.- 

 to qualitatively account for the appropriate re- 

 porting inadequacies. 



LITERATURE CITED 



ANTHONY. V. C. .^NT> J. .\. BRENN.^N. 



1974. An example of the by-catch piroblem on directed 

 fisheries for 1975. Annu. Meet. Int. Comm. Northwest 

 Atl. Fish.. Summ. Doc. 7-i 47 'Re%is€d i. Ser. No. 3386. 5 p. 



BREN'N.\N. J. A. 



1975. By-catch trends of selected fisheries operating in 

 ICNAF Subareas 5 and 6. Annu. Meet. Int. Comm. 

 Northwest Atl. Fish.. Res. Doc. 75 70. Ser. No. 3554, 14 p. 



BROWN. B. E.. J. A. BREN-N.\N. E. G. HEYERD.\HL, .4NT) R. C. 



Hen-n-emlth. 



1973. Effect of by-catch on the management of mixed 

 specie fi.gheries in Subarea 5 and Statistical area 6. Int. 

 Comm. Northwest Atl. Fish.. Redb. 1973. Part HI. p. 217- 

 231. 

 H.\DLEY. G. F. 



1962. Linear pn^ramming. Addison- Wesley, Reading. 

 Mass.. 520 p. 

 INTERNATIONAL COESOSSION FOR THE NORTHWEST ATIAN- 

 TTC FISHERIES. 



1969. Int. Comm. Northwest Atl. Fish. Annu. Proc. 19. 55 



P- 



1970. Int. Comm. Northwest Atl. Fish. Annu. Proc. 20. 47 



P- 

 1972a. Int. Comm. Northwest Atl. Fish. Annu. Proc. 22, 94 



P- 

 1972b. Int. Comm. Northwest Atl. Fish.. Stat. Bull. 21, 135 



P- 

 1974a- Int. Comm. Northwest Atl. Fish.. -Annu. Proc. 24. 



128 p. 



1974b. Int. Comm. Northwest Atl. Fish., Stat. Bull. 22, 239 



P- 

 1975a. Int. Co mm . Northwest AtL Fish. Annu. Rep. 25. 



116 p. 

 1975b. Int. Comm. Northwest Atl. Fish.. Stat. Bull. 23. 277 



P- 



1976. Int. Comm. Northwest Atl. Fish. Annu. Rep. 26, 139 



P- 

 19 / / . Int. Comm. Northwest Atl. Fish. Annu. Rep. 27, 84 



P- 



856 



