perceptibly upward, suggesting that the bottom- 

 fish resource adequately maintained itself dur- 

 ing the 5 years of fishing being reviewed here. 



That the total stock was not subjected to 

 excessive fishing is also indicated by above- 

 average yields of croaker during 1961-63 

 from nearshore grounds east of the Delta, 

 where intensive effort was expended each 

 year. 



To determine optimum fishing grounds for 

 the industrial bottomfish fishery of the north- 

 central Gulf, I compared average annual fish 

 abundance for the years 1959-63 and its 

 variability from year to year. This method 

 is similar to one developed by Klages (1942) 

 who delineated optimum geographical regions 

 for the production of certain agricultural 

 crops. The area with the highest average 

 (annual) abundance and the lowest coefficient 

 of variation represents the ground where, 

 over the years, average fishing success was 

 consistently greatest. 



By this means of assessment, the nearshore 

 area east of the Mississippi River Delta 

 (summer-fall) proved to be the most productive 

 bottomfish ground (table 8). Although year-to- 

 year fish abundance on the nearshore grounds 

 west of the Delta (summer-fall) was identical, 

 its annual variation was greater (17 percent). 

 Fish abundance on the nearshore grounds east 

 of the Delta during winter and spring was 



Table 8. --Average annual abundance and variability of 

 industrial bottomfish populations in the north-central 

 Gulf of Mexico, 1959-63 



Insufficient data. 



relatively high (0.54 tons per hour), but its 

 annual variation was the greatest of all four 

 areas. Each season the offshore grounds east 

 and west of the Delta harbored smaller con- 

 centrations of bottomfish than the nearshore 

 grounds. Annual variation in offshore stock 

 abundance was intermediate between com- 

 parable measures for nearshore grounds east 

 and west of the Delta. 



RECOMMENDATIONS 



As previously mentioned, the total catch of 

 bottomfish in the commercial shrimp fishery 

 within northern Gulf coast waters is unknown. 

 Quantitative analyses of commercial shrimp 

 catches from the grounds in the 5- to 10- 

 fathom depth range off St. Augustine, Fla., 

 have shown, however, that for every pound of 

 shrimp caught (whole weight) about 8-1/4 

 pounds of bottomfish were taken (Wolff, 1963). 

 A similar ratio was reported by Miles (1951) 

 in an analysis of fish caught by shrimp trawlers 

 operating in Apalachicola Bay and the adjoin- 

 ing Gulf of Mexico. In 1959, the catch of com- 

 mercial shrimp at 0-20 fathoms in the 

 Pensacola-Mississippi River coastal area was 

 6,500 tons, whole weight (Kutkuhn, 1962). If 

 the catch ratio of shrimp to fish is set at 1:8, 

 then the estimated catch of bottomfish by 

 shrimp trawlers totaled about 52,000 tons, or 

 nearly twice the amount landed by industrial 

 fish trawlers operating east of the Delta in 

 1959. It is noteworthy that the catch of men- 

 haden recorded for Mississippi in 1959 was 

 about 87,000 tons. 



Accordingly, the following suggestions are 

 offered to develop the potential of the bottom- 

 fish resource in the Gulf of Mexico: 



1. Because bottomfish caught during com- 

 mercial shrimping operations have the greatest 

 potential as raw material for the fish meal 

 industry throughout most of the year, they 

 should be retained and processed. 



2. More of the bottomfish concentrations 

 should be harvested on the offshore grounds 

 in 7 to 30 fathoms east and west of the Mis- 

 sissippi River Delta between June and August. 



3. Bottomfish stocks should be fished during 

 the winter when reduction plants and most 

 shrimp vessels must otherwise remain idle. 



SUMMARY 



The trawl fishery for industrial bottomfish 

 in the northern Gulf of Mexico has expanded 

 rapidly since 1952. Statistics reveal that from 

 1959 through 1963, the north-central Gulf of 

 Mexico annually produced between 38,000 and 

 48,000 tons of bottomfish for animal food 

 markets. Annual expenditures of effort over 

 the 5 years ranged between 63,000 and 106,000 

 hours of trawling. About 73 percent of the 



total production was taken from the area lying 

 between the Mississippi River Delta and the 

 approach to Mobile Bay. Catches in waters of 

 7 fathoms or less represented about 55 percent 

 of the Gulf total. Although overall landings 

 varied only moderately during the 5 years, 

 production fluctuated sharply at certain sea- 

 sons and in certain areas. Statistics showed 

 that the increased effort and catches made 



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