Fatty acid profiles of phyllosoma larvae of western rock lobster (Panulirus cygnus) in cyclonic and anticyclonic eddies of the Leeuwin Current off Western Australia

Abstract

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractThe recent dramatic decline in settlement in the population of the spiny lobster, Panulirus cygnus, may be due to changes in the oceanographic processes that operate offshore of Western Australia. It has been suggested that this decline could be related to poor nutritional condition of the post-larvae, especially lipid which is accumulated in large quantities during the preceding extensive pelagic larval stage. The current study focused on investigations into the lipid content and fatty acid (FA) profiles of lobster phyllosoma larvae from three mid to late stages of larval development (stages VI, VII, VIII) sampled from two cyclonic and two anticyclonic eddies of the Leeuwin Current off Western Australia. The results showed significant accumulation of lipid and energy storage FAs with larval development regardless of location of capture, however, larvae from cyclonic eddies had more lipid and FAs associated with energy storage than larvae from anticyclonic eddies. FA food chain markers from the larvae indicated significant differences in the food webs operating in the two types of eddy, with a higher level of FA markers for production from flagellates and a lower level from copepod grazing in cyclonic versus anticyclonic eddies. The results indicate that the microbial food web operating in cyclonic eddies provides better feeding conditions for lobster larvae despite anticyclonic eddies being generally more productive and containing greater abundances of zooplankton as potential prey for lobster larvae. Gelatinous zooplankton, such as siphonophores, may play an important role in cyclonic eddies by accumulating dispersed microbial nutrients and making them available as larger prey for phyllosoma. The markedly superior nutritional condition of lobster larvae feeding in the microbial food web found in cyclonic eddies, could greatly influence their subsequent settlement and recruitment to the coastal fishery.

Condition of larvae of western rock lobster (Panulirus cygnus) in cyclonic and anticyclonic eddies of the Leeuwin Current off Western Australia

“…As a result, the AEs have consistently been found to be more biologically productive than are CEs, supporting significantly higher zooplankton biomass and more abundant mesozooplankton, which could be expected to provide much better feeding conditions for a generalist predator of zooplankton, such as phyllosomas. The study of the fatty acid profiles of phyllosomas from CEs and AEs suggested that the microbial food web operating in cyclonic eddies may provide better feeding conditions for lobster larvae, which could explain this apparent contradiction (Wang et al 2014). On average, there is substantially more lipid per larva for the phyllosomas from CEs than for those from AEs for stage VIII.…”

Production and ecosystem structure in cold‐core vs. warm‐core eddies: Implications for the zooplankton isoscape and rock lobster larvae

“…Specific fatty acids and relatively high levels of sterols derived from dinoflagellates have previously been found to provide the dominant food chain signal in the phyllosoma of P. cygnus (Phillips et al ). Furthermore, a higher level of fatty acid markers for flagellates and a lower level of copepod grazing markers were found in P. cygnus phyllosoma sampled from CCEs vs. WCEs (Wang et al ).…”

“…However, phyllosomas are not usually found within the LC at this time, as most phyllosomas remain offshore and further south, in cooler and (at this time) less nutrient‐rich subtropical waters (STW). There are a number of possible explanations for this spatial mismatch of phyllosomas and their prey, including an improved availability or quality of food in STW (Wang et al , b , ), offshore reduction in predation on evolutionary time scales (Wasmund et al ; Säwström et al ), or improved opportunity to be transported or recruited to more desirable locations on the coast (Caputi ).…”

“…However, late stage phyllosomas caught feeding in CCEs were significantly richer in lipid and protein than those from WCEs (Wang et al ). Together, these studies leave the question unanswered as to why phyllosomas feeding in CCEs are in much better nutritional condition than their WCE counterparts (Wang et al ; O'Rorke et al ) even though surface Chl a concentrations are higher in WCEs.…”

Cardiorespiratory ontogeny and response to environmental hypoxia of larval spiny lobster, Sagmariasus verreauxi

“…Gaining an improved understanding of physiological constraints of spiny lobster larvae is vital for determining potential causal links between apparent recent declines in post larval recruitment and ocean change (Fitzgibbon et al, 2014a,b;Wang et al, 2014). There has been a down turn in coastal recruitment of pueruli, for a number of species around the world, which cannot be entirely explained by seasonal fluctuations in recruitment patterns or stock reproductive output (Caputi et al, 2013;Ehrhardt and Fitchett, 2010;Feng et al, 2011;Linnane et al, 2010Linnane et al, , 2013.…”