Larvae of the Hawaiian amphidromous goby Lentipes concolor settled after a mean length of larval life (LLL) of 86·2 8·5 days (n=236, range=63-106 days) at a mean size of 16·0 0·7 mm L T (n=154, range=14·1-17·9 mm). Mean LLL for L. concolor was about twice that typically reported for tropical marine gobiids. Variation in LLL (CV=10%) and size at settlement (CV=4%) were low, and comparable to that for marine gobiids. LLL and L T were weakly positively correlated (Pearson's correlation coefficient r=0·50, P<0·0001). Larvae settled after shorter planktonic lives and at smaller sizes during months with warmer ocean temperatures. Inter-island variation in LLL did not support a dominant south-east to north-west larval drift, following the dominant south-east to north-west flow of prevailing currents in the Archipelago. Instead, recruits on Maui Island, centrally located in the archipelago, had shorter LLL than recruits to upstream Hawai'i and downstream Kaua'i islands. These findings have important implications for understanding the complex life history dynamics of amphidromous fishes as well as their management. 2001 The Fisheries Society of the British Isles
Yellow tang Zebrasoma flavescens is the primary coral reef fish species taken in Hawaii for the aquarium trade. As part of an extensive adaptive management effort that included a network of marine protected areas that prohibited commercial aquarium fishing, an emphasis was placed on obtaining habitat-and sex-specific life history information for this valuable species. Using otolith and capture-mark-recapture methods we examined sexual differences in ontogenetic patterns of habitat use, growth rate, size dimorphism and longevity. Age validation using tetracycline to mark otoliths provided evidence that a single annulus formed each year. Yellow tang are a long-lived species (the oldest individual collected was 41 yr old) and display an asymptotic growth pattern typical of the family Acanthuridae. Median size and age at the transition between deeper coral-rich and shallow turfdominated habitat use were about 20 mm longer and about 2 yr older for males than females and coincided with an increase in reproductive output. The sexual difference in size at habitat transition, combined with sexual size dimorphism (mean asymptotic maximum length -male: 179 mm; female 156 mm) results in differences in the size distributions of both sexes in the 2 habitats. Sexual size dimorphism resulted from a higher growth rate for males through the juvenile period.KEY WORDS: Ontogenetic habitat use · Hawaiian aquarium fishery · Acanthuridae · Model selection · Otolith · Capture-mark-recapture · Growth · Coral reef fish
Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 389: [245][246][247][248][249][250][251][252][253][254][255] 2009 information is combined with ontogenetic patterns of habitat use. Most studies on ontogenetic variation of habitat use have compared size distributions between habitats (Gillanders et al. 2003), and therefore have not considered age structure, sex-specific habitat use patterns or the duration of the lifespan spent in each habitat. When available, information about age-based habitat use can improve conservation planning and design of MPAs (Mumby 2006, Parnell et al. 2006) and lead to an understanding of how the amount of available juvenile and adult habitat may influence population size -a potential key to conservation and area-based fisheries management (Halpern et al. 2005).Many species of coral reef fish, including several species of surgeonfish, make ontogenetic shifts in habitat use-an important factor in the organization of fish communities (Robertson 1988, Lawson et al. 1999, Lecchini & Galzin 2005, Robertson et al. 2005, Pratchett et al. 2008. Yellow tang in West Hawaii settle primarily into middepth (10 to 25 m) reef habitat with a high percentage of coral cover (hereafter deeper coral-rich habitat). At some as yet undetermined point in their lifespan, larger individuals shift to spending daytime foraging in adjacent, shallow, complex habitats (reef flats and boulders) characterized by a high percentage of exposed rock covered by turf algae (h...
Daily increment formation in sagittal otoliths, scaling between otolith and somatlc growth. and the temporal link between settlement and formation of a settlement mark in otolith structure were evaluated for their use in reconstructing aspects of the early Me history of the basalt goby Bathygobius coalitus. Formation of daily increments was validated in sagittae of fish ranging In Life history stage from new recruits to sexually differentiated males and females. Total length (TL) was proportional to other measures of body length, width, and depth, and linearly proportionaI to sagitta radius for fish between 8 and 40 mm TL. Somatic-otolith scaling became more curvilinear in larger fish due to declining growth rate of otoliths relative to TL, especially in fish collected during warmer sea surface temperatures. For fish 8 to 40 mm TL, somatic-otolith scaling was not affected by differential somatic growth rates nor by seasonal water temperature. A settlement mark, clearly identifiable as a distinct and abrupt shift in optical focal plane, contrast, and width of daily increments, was venfied to coincide with settlement. Wider post-settlement increments abruptly followed narrower pre-settlement increments across the settlement mark. These results support the use of daily increments, somatic-otolith scaling, and a settlement mark for reconstruction of hatch and settlement dates, mean daily pre-and post-settlement growth rates, size and age at settlement, and post-settlement size-at-age histories for the basalt goby.
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