Larval anchovy and sardine abundances between Punta Eugenia and Point Conception from 1963-2015

Anchovies and sardines are some of the most economically and ecologically important and well-studied fishes on earth but there is still uncertainty regarding how distributions and abundances change through time and space.  We bring together  larval abundance data for northern anchovy (Engraulis mordax) and Pacific sardine (Sardinops sagax) collected by United States and Mexican scientists over 50 years (1963-2015) to test the Basin and Asynchrony hypotheses. The Basin Hypothesis states that a species’ geographic range and spawning area (R) increases with overall abundance (A) according to a power law, R=aAb, where the exponent (b) is less than ~ 0.5 when the rate of increasing area occupied saturates as population size increases. The Asynchrony Hypothesis postulates that anchovy and sardine abundances are negatively correlated through time. We found that the Basin Hypothesis was supported for both species but the Asynchrony Hypothesis was not during this 53-year period.  Due to collabor..., CalCOFI and IMECOCAL collected fish larvae (ichthyoplankton) with obliquely-towed ring nets (1951 to 1977) and bongo nets (1978-present; Ohman and Smith, 1995; Thompson et al. 2017).  Detailed sampling protocols can be found in Kramer et al. (1972) and Smith and Richardson (1977), but, briefly, nets were towed to 140 meters (or within 15 m of the bottom at shallow stations) from 1951-1968 and then to 210 meters after 1968 (Ohman and Smith 1995).  Plankton in ring nets and starboard side of the bongo net were preserved in 5% buffered formalin, while, beginning in 1997, contents of the port side net were preserved in 100% ethanol (Gold et al. 2023); here, we focus on just formalin-preserved samples.  In the laboratory, all larval fishes were sorted from the rest of the plankton and identified to species.  Whereas it is not possible to identify all ichthyoplankton to species (e.g., rockfishes; Thompson et al. (2016)), anchovy and sardine are readily identifiable at all life stages. To acco..., , # Larval anchovy and sardine abundances between Punta Eugenia and Point Conception from 1963-2015

[https://doi.org/10.5061/dryad.zcrjdfnpm](https://doi.org/10.5061/dryad.zcrjdfnpm)

## Description of the data and file structure

The data here are larval abundances for anchovy and sardine collected from individual stations off the U.S. and Mexico from 1963-2015. 

The column, cruise depicts the numeric cruise number where the first two digits are the year and the second two the month when the cruise began.  For example, cruise 6301 was initiated in January, 1963.

The column ship is a two digit code referring to the ship that collected the larvae.  For example, \"BD\" is a ship named the Black Douglas.

CalCOFI/IMECOCAL has a system for the longitude and latitude of sample stations.  CalCOFI \"lines\" are are latitudinal and \"stations\" are longitudinal.  A sampling location with a lower the \"line\" number is further south, while a station with a lower value is closer to shore.

The columns l...