Winter warmth gave uncertain spring-to-summer anchovy catch slopes in four California samples in 1978-2019

We tested whether January-February sea temperature predicts spring catches relative to summer catches of northern anchovy larvae. We used 1,250 matched station-year pairs in two CalCOFI sectors and two periods from 1978 to 2019. Models controlled station, linear time trend, sampling date, light and effective water volume. All four slopes were positive, from +0.203 to +1.457 log-density units per C. All four intervals adjusted for four tests included zero. Station trends, presence-only outcomes, year weights and a short serial-dependence check did not establish a repeated link. The early models had only 13-14 sampled years. Many catches were zero. A seasonal catch contrast cannot identify a spawning date or separate transport, survival and abundance. Reporting completeness and detection remain uncertain. We test no pollution effect or causal climate effect. The package gives code, aggregate results, source hashes, checks and a figure. Raw records and record-level outputs remain outside the bundle.

anchovy · CalCOFI · phenology · seasonal catch · winter temperature · observation bias · matched stations · null result