Seasonal variation in hyperiid amphipod abundance and diversity and influence of mesoscale structures off Baja California

Abstract

Hyperiid amphipods collected during 4 IMECOCAL (Spanish acronym for Mexican Investigations of the California Current) cruises in January, April, July, and October 2005 were analyzed for seasonal variation in abundance and diversity and to determine the influence of surface circulation. The number of species was high in all seasons (between 79 and 92), but abundances showed remarkable differences. The total number of amphipods was lowest in January and highest in October (geometric means were 82 and 606 ind. 1000 m -3 respectively). Multivariate analysis based on similarity indices demonstrated a tight coupling between species composition and mesoscale structures. The largest cluster joined 67 stations, with 40% of similarity being explained by 4 species (Vibilia armata, Lestrigonus schizogeneios, Eupronoe minuta, and Primno brevidens). The geographic position of these stations coincided with the main California Current (CC) flow from spring to autumn. Subgroups were defined by minor seasonal differences. In contrast, the CC flow during winter was reduced to a meander off north Baja California, and was surrounded by oligotrophic water as indicated by the presence of the hyperiids Anchylomera blossevillei and Phrosina semilunata plus 3 of the dominant species (V. armata, E. minuta, and P. brevidens). To the south of this front, other clusters with high oceanic influence were formed. In 2005, 3 eddies were detected in the area: one anticyclonic eddy in April and 2 cyclonic eddies in July. The anticyclonic eddy located in the southwest had its own faunal cluster that had high diversity but low population density. The main species in the anticyclonic eddy was Platyscelus ovoides. Only one of the cyclonic eddies had a unique faunal identity, being strongly dominated by Vibilia armata; this was located in the north between the CC flow and the coast. The other eddy was large and situated in the middle of the area, with a faunal array analogous to that in the CC flow. Correlation between hyperiid and salp species abundances suggested that the increase in salps (Salpa fusiformis, Thalia orientalis, Cyclosalpa bakeri) in spring could be relevant, as many hyperiid species showed a strong increase at this time. However, the most correlated salp was Cyclosalpa danae, which occurred only in October. Chains of C. danae aggregates were firmly attached in the samples. This would promote the aggregation and survival of amphipod hosts, particularly small species such as Lestrigonus schizogenios and L. bengalensis.

Nutritional composition of potential zooplankton prey of spiny lobster larvae: a review

“…). Hyperiids were found to be scarce only in the most productive areas off Baja California Peninsula (Lavaniegos & Hereu ), which reinforces the suggestion of an oligotrophic habitat requirement for hyperiids (Vinogradov ), probably because they are closely associated with gelatinous zooplankton which are the most frequently major component of the zooplankton biomass in oligotrophic waters (Parsons & Lalli ).…”

Hyperiid amphipod community in the Eastern Tropical Pacific before, during, and after El Niño 1997−1998

“…A group of species including Phronima atlantica, Phronimella elongata, Phrosina semilunata, and some species of Primno was proposed by Vinogradov (1999) (Vinogradov 1991), the Gulf of California (Siegel-Causey 1982) and the CC area off Baja California (Lavaniegos & Hereu 2009), suggest a different trend. In the study area and in other tropical Pacific regions, Hyperioides sibaginis and Lestrigonus bengalensis were the most abundant (Gasca & Franco-Gordo 2008, Zeidler 1984, Valencia & Giraldo 2009).…”

“…There are still large neritic and oceanic areas in which basic aspects of this group have not been surveyed; this is true for part of the North and Central Pacific (Vinogradov 1999). Information about the hyperiids from the Eastern Pacific region has been mainly taxonomic (Brusca & Hendrickx 2005, Gasca 2009a, Gasca et al 2010, and none of the ecological contributions (Brusca 1967, Gasca & Haddock 2004, Lavaniegos & Hereu 2009) have been related to EN conditions. It has been documented that EN has important effects on the zooplankton communities of the Pacific Ocean (Fiedler 2002, Badán-Dangón 2003.…”

“…Attempts have been made to relate the occurrence of hyperiid species with water masses or oceanographic conditions (Bary 1959a,b, Kane 1962, Shulenberger 1977, Siegel-Causey 1982, Gasca 2004, Lavaniegos & Hereu 2009). Lavaniegos & Ohman (1999) provided data suggesting that hyperiids are sensitive to largescale climate changes.…”

Oceanographic mechanisms that possibly explain dominance of neritic tropical zooplankton species assemblages around the Islas Marias Archipelago, Mexico

“…This explains the relatively low mean abundance of hyperiid amphipods (917 ind 1000 m -3 ) at IMA as an amphipod coastal-oceanic species diversity gradient, although does not explain the relatively low amphipod species richness (15 species) (sampled at locations <30 m depth). However, it is clear that Islas Marías amphipods were clearly dominated by tropical-neritic amphipod species typical from the Panamic region (Valencia & Giraldo, 2009), being considerably different from California and Baja California peninsula regions, the Gulf of California, and Central region of Mexican Pacific (Lavaniegos & Ohman, 2003;Lavaniegos & Hereu, 2009).…”