The jack mackerel (Trachurus symmetricus) resource of the eastern North Pacific

Abstract

The jack mackerel before 1947, was of minor commercial importance having to take a back seat to the better known, more profitable, and more abundant Pacific sardine (Sardinops caeruleus) and the more desirable Pacific mackerel (Scomber japonicus). During these years it was referred to as "horse mackerel" and had relatively little market appeal. Much of the catch between 1926 and 1946 was absorbed by the fresh fish markets and consisted primarily of jack mackerel taken from mixed sardine and Pacific mackerel schools. Landings were low, varying between 183 and 15,573 short tons. During the 1947-48 season, the industry, after being hit hard by poor sardine landings, turned to the jack mackerel as a substitute sardine and landed approximately 71,000 short tons. Jack mackerel have been a major contributor to California's commercial landings ever since (Figure 1). In 1948, the U.S. Pure Food and Drug Administration authorized the use of the common name jack mackerel on all labeling. This name was expected to have more consumer appeal than the original official name "horse mackerel". The California Department of Fish and Game commenced routine length and age sampling of the commercial landings in 1947, the year the fishery first blossomed into being. Due to the apparent healthy condition of the resource and the need for emphasis on other fisheries these sample data have not been subjected to a complete analysis. We have recently completed the assignment of ages to the otoliths sampled and anticipate dedicating most of our effort in 1968 to writing a manuscript describing the fishery, its year-class composition and other factors affecting the yield. The literature on the jack mackerel is somewhat scanty with the greatest part of it pertaining to: (i) taxonomy; (ii) egg and larva distribution, and survival; (iii) yield per area from California waters; and (iv) reviews of the jack mackerel fishery in California and preliminary discussions of biological knowledge. Accordingly, for this paper, I have called upon past work and much unpublished data from our files, including station data from pre-season albacore cruises and the previously mentioned length and age data. (Document has 13 pages