Cephalopod paralarval species richness, abundance and size structure during the 2014-2017 anomalous warm period in the southern Gulf of California

Abstract

Cephalopod paralarval species richness, abundance and size structure were surveyed wduring an anomalous warm period (2014-2017) in the Cabo Pulmo National Park (CPNP), Gulf of California, Mexico. Paralarval taxa from six families (Cranchiidae, Enoploteuthidae, Ommastrephidae, Onychoteuthidae, Argonautidae and Octopodidae) were identified. Most taxa were of tropical biogeographic affinity and oceanic habitats. Highest paralarval richness occurred during spring associated with the northward movement of Tropical Surface Water, while the lowest was recorded during autumn with the southward flow of the Gulf of California water mass. Although 89% of the paralarvae were collected at or close to their species hatching size, none of the paralarval taxa showed a consistent seasonal spawning period. A canonical correspondence analysis showed three taxonomic assemblages: Argonauta and Helicocranchia-Onychoteuthis groups correlated with northward currents and high zooplankton biovolumes (ZB) and SD complex-Abraliopsis group with southward currents and intermediate ZB. Our Helicocranchia pfefferi paralarvae are the first recorded for the Gulf of California. At least 11 cephalopod taxa reproduce in CPNP. This area represents a suitable spawning habitat for cephalopods of socio-economic value.