5 EXPLOITATION 



5.1 Fishing equipment 



5.11 Gears 



Jack mackerel have been taken incidentally 

 to the sardine and Pacific mackerel fisheries 

 for many years by the same gear used in these 

 fisheries. When the mackerel fishery developed 

 suddenly in 1947 because of the decline in 

 sardines and to a lesser extent Pacific mack- 

 erel, the purse seines of the sardine and Pa- 

 cific nnackerel fishery continued to be used 

 for the jack mackerel. Scofield (1951) de- 

 scribed in detail purse seines and other round 

 haul nets that have been used in California 

 fisheries. Before the development of the fishery 

 for jack nnackerel they were also taken in 

 small quantities in the ring nets and lampara 

 nets used by the sardine fishery before the 

 purse seine came into general use. 



Jack mackerel are also taken by the fisher- 

 men who fish for Pacific mackerel for the 

 fresh fish market and to a lesser extent for 

 canneries. Various methods have been and are 

 used in this fishery, including hand lines, long 

 lines, jigs, gill nets, and scoop nets, often in 

 conjunction with chumming and/or lights 

 (Croker, 1933, 1938). 



Improvements in ship gear and fishing 

 methods of the purse seine fleet include in- 

 stallation of ship-to-ship radios, echo-sound- 

 ing gear, and power blocks, and the use of 

 nnotor skiffs, synthetic netting nnaterials, and 

 airplane scouting. 



5.12 Boats 



The jack mackerel is taken primarily as 

 a substitute or alternate cannery fish by the 

 sardine fishing fleet. The sardine fleet con- 

 sists of large purse seiners (over 60 feet or 

 18.3 meters in length) and assorted smaller 

 purse seiners and lampara boats that are used 

 in other fisheries when sardines are not avail- 

 able. Since the big increase in jack nnackerel 

 landings in 1947, this fleet attained its largest 

 size during the 1949-50 season when it con- 

 sisted of 372 vessels (including 135 smaller 

 boats). In the 1960-61 season the California 

 sardine fleet consisted of only 28 vessels 

 (11 large purse seiners, 2 small purse seiners, 

 and 15 lampara boats). 



5.2 Fishing areas 



Most jack mackerel are landed in the Los 

 Angeles area (Roedel, 1953). Because this 

 fishery is so closely allied to the sardine 

 fishery, the area of the jack mackerel fishery 

 closely coincides with that of the sardine 

 (Fig. 6). The purse seiners are primarily 



seeking sardines; if sardines are scarce and 

 there is a market for jack mackerel, these 

 fish are taken instead whenever encountered. 

 Actually the jack mackerel is distributed 

 farther offshore than the sardine. In the 1 952- 53 

 sardine season the sardine catch was only 

 about 3,000 tons, compared to over 120,000 

 tons the previous year. In the same season the 

 jack mackerel catch was a record 73,000 tons, 

 but 67 percent of this catch was made in the 

 Tanner Bank-Cortez Bank area about 80 nauti- 

 cal miles offshore (Clothier and Greenhood, 

 1956). When sardines are more abundant the 

 purse seiners do not range so far offshore. 



Jack mackerel are also taken in unknown 

 but relatively small amounts by Mexican purse 

 seiners off northern Baja California. 



In southern California and to a lesser extent 

 in central California, jack mackerel are taken 

 in small quantities primarily for the fresh 

 fish market. 



5.3 Fishing seasons 



Clothier and Greenhood (1956) stated: "Jack 

 mackerel are present in the waters off Cali- 

 fornia throughout the entire year, but since 

 the fishery is carried on simultaneously with 

 the sardine and Pacific mackerel fishery, and 

 these species are taken chiefly during the fall 

 and winter months, the jack mackerel landings 

 decline to a minimum in the spring and early 

 summer." 



5.4 Fishing operations and results 



5.41 Effort and intensity 



Effort and intensity are so influenced by 

 the relationship to the sardine and Pacific 

 mackerel fisheries as to be meaningless. 



5.42 Selectivity 



Selection factors primarily involved are the 

 fishermen's ability to identify the species, size 

 of school, and size of fish before setting their 

 nets. 



5.43 Catches 



Table II gives the catch of Pacific nnackerel, 

 jack mackerel, and all mackerel for the years 

 1916-63, 



6 PROTECTION AND MANAGEMENT 



6.1 Regulatory measures 



6.11 Limitation or reduction of total 

 catch 



There are no legislative limitations on 

 catch specifically pertaining to the jack mack- 

 erel. Canneries often place limits on the ton- 

 nage of jack mackerel that they will accept. 



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