Habitat factors controlling Pacific herring (Clupea pallasi) egg loss in Prince William Sound, Alaska

• Published in: Canadian journal of fisheries and aquatic sciences 1999-06, Vol.56 (6), p.1133-1142
• Main Authors: Rooper, C N, Haldorson, L J, Quinn, TJ II
• Format: Article
• Language: English
• Subjects: Clupea pallasi; USA, Alaska
• ISSN: 0706-652X; 1205-7533
• DOI: 10.1139/cjfas-56-6-1133

Recruitment for many marine fishes is believed to be determined at an early life history stage. Pacific herring (Clupea pallasi) spawn in the intertidal and shallow subtidal zones and have a demersal egg stage that is susceptible to egg removals during incubation. Data were collected by the Alaska Department of Fish and Game in four years in Prince William Sound, Alaska, to identify important factors contributing to egg removals. We constructed analysis of variance models based on physical and biological variables to determine which environmental factors control egg loss rates. The habitat variables examined at each study transect were depth, wave exposure, north-south location, substrate, vegetation, mean bird abundance, abundance of loose eggs, and fish predation. Depth of spawn was the primary factor determining egg loss. Cumulative time of air exposure over incubation was substituted into the model for depth. Using the model, the total estimated egg loss from spawning to hatching ranged from 67 to 100% with an average of 75% (SE = 3.3%) in 1995. Eggs were originally deposited from 4 to -6 m depth relative to mean low water. The majority of eggs that remained in the spawning beds to hatching were deposited from 1 to -4 m depth. Egg removals due to avian predation were probably responsible for extreme egg loss rates at shallow depths.Original Abstract: Chez de nombreuses especes de poissons marins, le recrutement semble determine dans les premiers stades de developpement. Le hareng du Pacifique (Clupea pallasi) fraye dans la zone intertidale et dans la zone infratidale peu profonde, et ses oeufs demersaux peuvent disparaitre durant l'incubation. L'Alaska Department of Fish and Game a recueilli durant quatre ans des donnees dans le golfe du Prince-William, en Alaska, pour etablir les facteurs importants responsables de la disparition d'oeufs. Nous avons construit des modeles d'analyse de variance fondes sur des variables physiques et biologiques pour etablir quels facteurs environnementaux determinent les taux de perte d'oeufs. Les variables de l'habitat qui ont ete prises en consideration dans chaque transect de l'etude sont les suivants: la profondeur, l'exposition aux vagues, la localisation selon l'axe nord-sud, le substrat, la vegetation, l'abondance moyenne des oiseaux, l'abondance des oeufs libres et la predation par les poissons. La profondeur a laquelle la fraye etait effectuee etait le principal facteur determinant la perte d'oeufs. La duree cum