David L. Stein

Aspects of reproduction, early life history, and biology of macrourid fishes off Oregon, U.S.A.

Abstract Egg sizes, fecundities, times of spawning, early benthic life, size frequency, and distribution by sex and size are described for some of the four most common macrourid species off Oregon: Coryphaenoides acrolepis, C. armatus, C. filifer and C. leptolepis . Sizes of eggs at comparable developmental stages from different species were quite different. Average fecundities ranged about 26,000 to 2,500,000 eggs. C. acrolepis and C. filifer may spawn semi-annually. Juveniles of the three sympatric species, C. armatus, C. filifer , and C. leptolepis , become benthic in habit at different sizes. Different mouth size of each species may minimize competition for food. Size frequency distributions were either unimodal ( C. filifer, C. armatus ) or bimodal ( C. acrolepis, C. leptolepis ). However, small C. filifer were rarely collected suggesting that they remain pelagic longer than the young of other species. C. armatus and C. leptolepis were ‘bigger-deeper’, but the trend was not evident in the other two species. Sex ratios also differed: male C. armatus and C. leptolepis were less abundant than females, although their proportion increased with distance offshore. Numbers of males and females were about equal in C. acrolepis and C. filifer . Little evidence for the existence of sexual segregation was found. The liver apparently serves as a buoyancy mechanism in large C. armatus .

Towing large nets by single warp at abyssal depths: methods and biological results

Abstract Adequately sampling deep-water nekton is difficult because of the great time required for tows, avoidance of nets by larger animals, and the sparse fauna. These problems have been compounded by the small nets usually used for such sampling. This paper describes the equipment, techniques, difficulties, and results of towing large midwater and bottom trawls single warp at depths below 2000 m from chartered commercial fishing vessels. Use of large nets (107 m 2 mouth pelagic rope trawl and 29.6 m headrope otter trawl) is a method which minimizes the effects on sample sizes and compositions of the above factors. Tows with large opening-closing midwater trawls and otter trawls between 2000 and 4300 m off northern California collected specimens of rare species and unusually large individuals of other species. Included among these are five fish species not previously reported from off California: Bathysaurus mollis (Synodontidae), Barathronus pacificus (Aphyonidae), Echinomacrurus occidentalis (Macrouridae), Dysalotus oligoscolus (Chiasmodontidae), and Bellocia alvifrons (Alepocephalidae). Fishes decreased with depth by numbers of species, numbers of individuals, and by weight. Decapod crustaceans did not show similar trends. Cephalopods were uncommon at all depths sampled. Coryphaenoides filifer (Macrouridae), a nominally benthic fish species, was unexpectedly abundant in midwater between 2000 and 3100 m. It constituted 54.6% of the fish biomass collected at these depths. Its abundance did not appear to be related to sex, size, or reproduction. Food habits of Coryphaenoides armatus and C. yaquinae (Macrouridae), the most abundant benthic fish species, differed. The former ate primarily nekton; the latter, benthic infauna. Occurrence in stomachs of beaks from shallow living squid and of epipelagic barnacles suggests that carrion may form a significant part of the diets of these species. One ripe and five ripening female C. armatus , all longer than 740 mm TL, were collected. Estimated fecundity of the ripest was 6.2 × 10 6 eggs. Based on these and previous captures, C. armatus females mature at a large size, have a high fecundity relative to other macrourids, may not spawn simultaneously, and may be semelparous.

Description and occurrence of macrourid larvae and juveniles in the northeast Pacific Ocean off Oregon, U.S.A.

Abstract Although there are over 100 species of North Pacific macrourids, few of their larvae have previously been identified to species. Descriptions of postlarvae and juveniles of Coryphaenoides acrolepis, C. filifer, and C. leptolepis are given, with a provisional key to the identification of most species known from off Oregon. Vertical distribution of the larvae and juveniles of C. acrolepis apparently changes with ontogenetic development, the smallest individuals occurring shallowest. Macrourid eggs have not yet been identified from Oregon waters.

A Review Of The Snailfishes (Liparidae, Scorpaeniformes) Of New Zealand, Including Descriptions Of A New Genus And Sixteen New Species

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Bassogigas profundissimus (Roule) 1913 (Pisces: Brotulidae) from the North Pacific Ocean

Abstract Two specimens of Bassogigas profundissimus (Pisces: Brotulidae) are reported from Tufts Abyssal Plain in the North Pacific Ocean. These specimens are the first from the Pacific Ocean, the largest known (one 302 mm SL, the other ca. 230 mm SL), and the shallowest (5180 m) captured. Allometric growth in head length, horizontal eye diameter, and dorsal, anal, and pectoral fin lengths is evident. The swimbladder of each fish is contained in a tough, inelastic capsule.