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Larvae of Asemichthys taylori were reared in the laboratory to identifiable juveniles. A preserved series of larvae was characterized in part by fin meristics (X–XI, 14–15 dorsal fin rays; 15 anal fin rays), as well as a combination of the alignment of the jaw tip with the ventral margin of the gut, heavy lateral melanistic pigment except on the caudal peduncle, and a series of postanal ventral melanophores. An internal, horizontal band of melanin extends through the head from the snout to the gut. Hypural plates do not align vertically even after settlement, giving the appearance that the larvae do not complete notochord flexion during their planktonic stage. Larval A. taylori resemble known larvae of Radulinus spp., a genus under which some authors have synonymized the monotypic genus Asemichthys.

In the Strait of Georgia and Howe Sound, British Columbia, colonies of individual cloud sponges, growing on rock (known as sponge gardens) receive resource subsidies from the high biodiversity of epifauna on adjacent rock habitats. Bioherms are reefs of glass sponges living on layers of dead sponges. In the same area as the sponge gardens, newly discovered bioherms in Howe Sound, BC (49.34.67 N, 123.16.26 W) at depths of 28- to 35-m are constructed exclusively by Aphrocallistes vastus, the cloud sponge. The sponge gardens had much higher taxon richness than the bioherms. The sponge garden had 106 species from 10 phyla, whereas the bioherm had only 15 species from 5 phyla. For recruiting juvenile rockfish (quillback, Sebastes maliger), the food subsidy of sponge gardens appears to be missing on bioherms of cloud sponge, where biodiversity is relatively low. While adult and subadult rockfishes (S. maliger, S. ruberrimus, S. proriger, and S. elongatus) were present on bioherms, no evidence for nursery recruitment of inshore rockfishes to bioherms was observed, whereas the sponge gardens supported high densities of newly recruited S. maliger, perhaps owing to the combination of both refuge and feeding opportunities. These results indicate that sponge gardens form a habitat for early stages of inshore S. maliger, whereas A. vastus bioherms are associated only with older juvenile and adult rockfishes.

Abstract The spot prawn, Pandalus platyceros Brandt, 1851, predominantly uses kelp beds of Agarum sp. as nursery habitat in waters of southern British Columbia. Census data indicate interannual fluctuations in numbers of shrimp settling into nurseries. Analysis of size samples indicates settlement primarily in May and June, with lesser rates of settlement through the summer. Growth of about 3 mm CL per month can occur through summer and fall, with juveniles apparently emigrating from nurseries, starting in the fall, at sizes of 16-20 mm CL. Juveniles which fail to reach such size before winter remain in the nursery habitat, with slower overall growth at about 1 mm CL per month. This difference in duration of residence in kelp bed nursery habitat, together with different juvenile growth rates, leads to the conclusion that the age of spot prawns at a given size will be variable. Due to this variable early life history and growth, length frequency modes of spot prawns could include a mixed age group.

Pandalid shrimp larvae in protected Northeast Pacific marine waters are opportunistic hitchhikers, riding piggyback on jellyfish having a bell diameter similar to the leg span of the shrimp. Ridden medusae pulsed faster and for longer periods than unridden ones. Ridden medusae rested or fed only one-third as long as they swam, whereas the resting and feeding bouts of unridden medusae normally lasted twice as long as swimming bouts. The shrimp neither damage the jellyfish nor take food from them, but many of the ridden jellyfish apparently die, perhaps because of increased energetic load.

Domestication becomes significant in captive propagation of high-fecundity animals which sustain significant mortality rates. The domestication process typical of higher vertebrates has been observed in the coonstripe shrimp, Pandalus danae, which were reared through 10 generations for study of protandric hermaphroditism. The research protocol of repeated handling, for determining sex and carapace length, rendered escape responses maladaptive. Domesticated, F10 shrimp showed significantly greater band-sharing in genomic DNA than wild shrimp, and the domesticated shrimp had only 5.5% of the dopamine levels in haemolymph found in wild shrimp. For both parameters, outcrossed shrimp (wild X domestic) had intermediate values. The outcrossed shrimp looked entirely wild, yet had behavioral and metabolic attributes of domestic shrimp. For such nonendangered species, domestication may be as desirable as it is unavoidable. It appears necessary, however, to perform outcrossing in order to maintain the wild form. © 1993 Wiley-Liss, Inc.

Lingcod, Ophiodon elongatus, is a nest-guarding marine fish of western North America. Breeding occurs in late winter and early spring after males establish territories and guard nest sites therein. Eggs deposited as clutches in the nest site hatch ∼7 weeks after fertilization. We evaluated the level of genetic variation in lingcod spawning in the central Strait of Georgia through analysis of microsatellite and mitochondrial D-loop variability in fertilized egg samples collected from guarded clutches. Reconstructed parental genotypes displayed a high level of allelic diversity and observed heterozygosity (83–91%) over five microsatellite loci. Progeny of a single clutch were invariably derived from a single mother and between one and five fathers. Multiple egg samples were collected from inside and outside positions on 13 lingcod egg clutches in February 2002. Fin clip samples provided microsatellite genotypes for six of the nine guardian males. Analysis of between 33 and 306 eggs from each clutch indicated that each of the 13 clutches was produced by a different mother and five of them were sired entirely by the attendant male guardian. Eight clutches were sired by multiple males, with neighboring male guardians frequently involved in clutch fertilization. Known guardian males accounted for at least 78% of observed egg fertilization, although non-territorial males were observed and may have participated in spawning. Egg fertilization by individual males was spatially heterogeneous throughout egg clutches. One male guardian failed to fertilize detectable numbers of eggs in his own or any other clutch within the study area and may have been an adoptive father. The polygynous mating structure of lingcod may help maintain genetic variation in the species.

Near Vancouver, Canada, Clinocottus acuticeps spawns circular monolayer egg masses on rock surfaces at the 3.0- to 3.7-m tide levels from January through April. At these tide levels, air exposure occurs about half the time and most egg masses have clumps of Fucus distichus lying over them during low tides. Controlled removal of the F. distichus demonstrated a role of this plant in reducing egg mortalities and a preference by adult fish to spawn under macrophytic algae.Early embryonic stages were most susceptible to mortalities resulting from removal of cover plants in the field. In laboratory air-exposure tests, desiccation was more important than temperature elevation in causing mortalities.

Although planktonic drift is presumed for larvae of most marine fish species, the extent of larva dispersal by intertidal species is largely unknown. Oblique tows with a net of 500-μm mesh were made at distances of 0, 4, 20, and 500 m from steep rocky shores, divers guiding the 0-m tows. Ichthyoplankton of the extreme nearshore area was more dense than that of offshore waters. Species composition shifted radically from inshore to offshore; intertidal species (cottids, stichaeids, pholids, gobiesocids) were dominant inshore. Larvae of rocky intertidal fishes occurred more frequently along rocky shores than on an adjacent sandy beach. The evidence suggests that larvae of rocky intertidal fishes resist offshore and possibly longshore dispersal. In contrast to information for sandy beaches, data for the rocky nearshore area reveal that all stages of larvae remain inshore, not just those within a narrow size range. Populations of rocky intertidal fishes may thus be relatively isolated genetically.

Various species of marine fish larvae were reared in the laboratory to allow observation of the substratum preferences of newly settling fish. The range of preferences for settling larvae of intertidal species corresponded to the adult niche breadth. The preferred substratum was always an element of the adult habitat, although not necessarily the same substratum preferred by the adults. Experiments with artificial substrata indicated that settlement preferences are based on tactile cues and light transmission. Depending upon the species, other factors such as current speed or salinity can also influence settlement.

Captive-bred offspring from a single pair ofAmphiprion frenatus displayed two independent color polymorphisms, one for juvenile stripe pattern and one for adult color. The adult polymorphism encompassed color morphs representingA. frenatus, A. rubrocinctus andA. melanopus. Positive assortative mating occurred, with viable F2 offspring from one pairing. Hybridization has been achieved previously betweenA. melanopus, A. frenatus andA. ephippium, so these four species may be stable polymorphs of a single species, the different morphs selectively maintained in different geographic regions. The extent of polymorphism among marine fishes is poorly understood.

Egg masses of Xiphister atropurpureus (Kittlitz) and X. mucosus (Girard) are tended by a single adult male wrapped closely around the mass. Males tend up to three egg masses at once. It is suggested that males only tend egg masses that they have fertilized. Comparison of egg numbers in spawned masses and in ovaries of gravid females, together with the observation of complete egg extrusion by spent females, demonstrates that each mass comprises the entire annual egg output of a female. Therefore, during a season a male may repeatedly spawn with different females.

In Barkley Sound, Vancouver Island, Canada, the spawning of the black prickleback, Xiphister atropurpureus, occurs during winter on rocky beaches protected from wave action. However, during spring, spawning occurs on rocky beaches of increasing exposure. This species spawns only under boulders with pebble, small rock, or shell substrates. Coincident reduction of wave action and increases in temperature probably cause the seasonal shift in the spawning site of this stichaeid.

Late larval stages of the Pacific herring, Clupea harengus pallasi, which normally swim in schools, were reared in isolation from conspecifics to determine if schooling behavior is a requirement for metamorphic development. There were no mortalities resulting from prevention of schooling.