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

Abstract

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.

Predation of Northern Pike (Esox lucius L.) Eggs: A Possible Cause of Regionally Poor Recruitment in the Baltic Sea

“…In Blekinge, perch, rudd and roach were all seen eating eggs. Another possibility, not investigated by this study, is that avian or other egg predators may have contributed to egg loss (Rooper et al, 1999).…”

“…However, all these factors would simply increase mortality and not lead to the physical removal of eggs from the spawning site. Heavy wave actions may detach demersal fish eggs or even remove spawning substrates (Rooper et al, 1999); however, the weather in the end of April and beginning of May was calm in 2001 and all spawning along the coast took place in sheltered bays. Other physical forces, such as water currents, could explain some of the egg loss in the streams: unattached eggs were found on the sediment in the mouth area of Kronoba¨cken and Ryssbya˚n.…”

Vertebrate exploitation of pulsed marine prey: a review and the example of spawning herring

“…Egg mortality is high (e.g., Palsson 1984;Rooper 1996). Principal abiotic causes of mortality include desiccation of intertidal eggs, suffocation of eggs deposited in thick layers (e.g., over 100 eggs thick, and over a million eggs/m 2 ), strong wave action, and deposition at excessive depths (Outram and Humphreys 1974;Blaxter and Hunter 1982;Haegele and Schweigert 1985;Hay 1985;Rooper 1996).…”

“…Principal abiotic causes of mortality include desiccation of intertidal eggs, suffocation of eggs deposited in thick layers (e.g., over 100 eggs thick, and over a million eggs/m 2 ), strong wave action, and deposition at excessive depths (Outram and Humphreys 1974;Blaxter and Hunter 1982;Haegele and Schweigert 1985;Hay 1985;Rooper 1996). Fish (including herring) and invertebrates can be important predators (Wespestad and Barton 1979;Palsson 1984;Hay 1985;Haegele 1993b;Rooper 1996). Most studies of egg predation, however, have focused on birds (see below).…”

On the external and parental effects in early development of herring (Clupea pallasi) at the NE Kamchatka

“…Large differences in water level occur from flood to ebb. During ebbs a great part of eggs on bottom vegetation dry up, and the temperature in the remaining small pools rises sharply (Panin, 1950;Galkina, 1960;Dushkina, 1973;Rooper et al, 1999). Short-term temperature changes (from flood to ebb) have reached from 4.4 to 12.7 • C on herring spawning places in the Gulf of Korf and adjacent waters (Panin, 1950) and from 7 to 15 • C in the habitats of Okhotsk herring embryos in Tunguzka Bay (Galkina, 1960).…”