Age at recruitment of Hawaiian freshwater gobies

Abstract

SynopsisVery little is known about the dynamics of native Hawaiian stream fishes. Five species are restricted, as adults, to freshwater streams and estuaries on the major islands of the Hawaiian archipelago. This paucity of information is partly due to difficulties inherent in determination of age and subsequent determinations of life history characteristics. In the present study, we determined the age of newly recruited Hawaiian gobies, Stenogobius genivittatus and Awaous stamineus using otolith microtechniques. Internal otolith increments were enumerated using scanning electron microscopy (SEM). Increments of newly recruited juveniles were deposited on a daily basis as validated through a marking study. Results showed recruitment at an average age of 135 and 161 days for these two species, respectively, with more rapid growth following recruitment to freshwater. Chemical analyses of otolith carbonate of the Hawaiian gobies by electron microprobe for strontium and calcium concentrations provided valuable insights into a fish's past history. A combination of structural and chemical analyses makes it possible to link growth and recruitment to nutritional and environmental factors. Such information developed as a broad model would be applicable to the management of Hawaiian gobies and would greatly improve the quality of information available for these unique fish populations and other fish populations.

Evaluation of periodic and aperiodic otolith structure and somatic-otolith scaling for use in retrospective life history analysis of a tropical marine goby, Bathygobius coalitus

“…Embryonic duration for Bathygobius coalitus was assumed to be approximately 3 d based on the embryonic duration determined for the congeneric frillfin goby B. soporator (Tavolga 1954). Assuming that the first otolith increment was formed at hatch (Mder & Storck 1982, Nishirnura & Yamada 1984, Victor 1986a,b, Eckrnann & Rey 1987, Kingsford & Milicich 1987, Radtke et al 1988, Sponangle & Cowen 1994, age estimates were adjusted to account for embryonic duration by adding 3 d to daily increment counts. This correction procedure reduced the overestimation of mean daily growth rate (i.e., TL , , , , , , , /age), by accounting for embryonic growth as a component of TL at capture.…”

“…Settlement marks occur in the otoliths of a variety of fishes, including both amphidromous (Stenogobius hawaiiensis, Awaous guamensis, Radtke et al 1988) and marine (Coryphopterus glaucofraenum and Gnatholepis thompsoni, Sponaugle & Cowen 1994) gobies. They occur with a broad range in width and distinctiveness among various fishes, which may result from phylogenetic, biological, or environmental factors (Brothers & McFarland 1981, Victor 1983, Radtke et al 1988, Fowler 1989, Sponaugle & Cowen 1994, Wilson & McCormick 1997.…”

“…They occur with a broad range in width and distinctiveness among various fishes, which may result from phylogenetic, biological, or environmental factors (Brothers & McFarland 1981, Victor 1983, Radtke et al 1988, Fowler 1989, Sponaugle & Cowen 1994, Wilson & McCormick 1997. Wilson & McCormick (1999) classified settlement marks of tropical reef fishes into 3 categories: Type I shows abrupt marks characterized by a rapid decrease in increment width over settlement; Type 11, zonal marks characterized by a band of increments that are wider than pre-settlement increments; and Type 111, gradual marks characterized by a gradual decrease in increment width during settlement.…”

“…The structure of settlement marks appears to be taxon-specific, however, and may be subject to spatial and temporal variation (Wilson & McCormick 1997. Settlement may also occur with no coincidence of disruption to regular otolith structure, or may result in the deposition of settlement marks varying in composition from 1 to 2 increments to a wide multi-incremental transitional zone (Brothers & McFarland 1981, Victor 1982, Pitcher 1988, Radtke et al 1988, Fowler 1989, Hare & Cowen 1994, Sponaugle & Cowen 1994, Wilson & McCormick 1997. As a result, the species-specific structure of settlement marks must be investigated, the temporal link between formation of a settlement mark and settlement must be verified.…”

High gene flow due to pelagic larval dispersal among South Pacific archipelagos in two amphidromous gastropods (Neritomorpha: Neritidae)

“…However, although a community ecologist would view them as freshwater animals (for example, Bandel and Riedel, 1998;Smith et al, 2003), their population ecology may be more similar to that of a marine species, because of their pelagically dispersing larvae. Relatively long pelagic larval durations (PLDs) have been estimated from laboratory cultures of amphidromous gastropod veligers (40-98 days, Holthuis, 1995;Kano, 2006) and the otoliths of amphidromous Galaxiid fishes and gobies (63-266 days, Radtke et al, 1988Radtke et al, , 2001Mcdowall et al, 1994;Hoareau et al, 2007b). These PLDs fall at or above the high end of the range found in the planktotrophic larvae of marine invertebrates (7-293 days, Shanks et al, 2003) and fish (B20-90 days, Brothers et al, 1983).…”