Diurnal vertical movements in black sea bass (Centropristis striata): Endogenous, facultative, or something else?

Abstract

Fishes commonly exhibit diel rhythms in movements with consequences to feeding, reproduction, predator evasion, and resting. Such behaviors are conceived as plastic, persisting for phases (days to weeks), and then becoming disrupted, masked, and altered by changed environmental or ecological conditions. In telemetered black sea bass Centropristis striata (family Serranidae), we documented a remarkable 4-month record of persistent diurnal vertical movements. Within the U.S. Mid-Atlantic Bight June-October 2019 setting, biotelemetry data of 31 fish were examined through time series analysis and generalized additive modeling. Sun altitude played a dominant role throughout the series, where movements were diurnal. Thermal conditions were uniform until a September hurricane caused a 10°C rise in inhabited waters within the span of six hours, the result of water column mixing. This and other storms caused short-term disruptions (<2 d) to diel rhythmicity. Daytime vessel traffic, but not dolphin presence, caused ≤1 h refuge-seeking excursions. The discovery of pelagic behaviors (up to 15 m off the seabed) requires revision to the species' natural history, which was previously conceived as exclusively demersal. Spring-autumn movement functions included reef recruitment and evacuation, courtship and spawning, and seasonal changes in feeding ecology and predator fields. Throughout these phases, the cycle of daytime movement and nighttime inactivity persisted. We hypothesize that during the nocturnal period these visual specialists become immobile and thus evade predation and mobilize energy toward growth, reproduction, and storage. Because this function does not change from spring through autumn, we speculate that nocturnal quiescence serves as the proximate control for the diurnal activity cycle.

Clustering and classification of vertical movement profiles for ecological inference of behavior

“…Dynamic time warp (DTW) clustering is a method of unsupervised machine learning that identifies groups of similar time series by allowing the time series to be offset in time and length, thereby avoiding high dissimilarities between entities that are similar in shape but differ only in spatiotemporal offset (Lee et al, 2020). Despite being an older technique most popular for speech classification, DTW clustering methods have only recently been applied to animal movement data (Cleasby et al, 2019; Frankish et al, 2020; Secor et al, 2021). Convolutional neural network (CNN) image classification models are a form of supervised machine learning that have often been applied to video or image data for species classification (Siddiqui et al, 2018; Tabak et al, 2018; Willi et al, 2018) or animal detection (Salman et al, 2020).…”

Fish distribution in three dimensions around the Block Island Wind Farm as observed with conventional and volumetric echosounders

“…Side-looking acoustic systems (multibeam, acoustic lens [adaptive resolution imaging sonar and dual-frequency identification sonar]) and optical systems may be required to sample fauna inside structures (e.g., van Hal et al 2017). Black Sea Bass aggregate at reefs and structures (Fabrizio et al 2014;Secor et al 2021;Wilber et al 2022b), and they were the largest component of our catch. The aggregations of Black Sea Bass to the south of WTG-5 did not appear to be associated with WTG-5 in the sense that we did not see corridors of fish connecting the fish at WTG-5 and the aggregations.…”

Artificial structure selection by economically important reef fishes at North Carolina artificial reefs

“…Given the value of these species among fishers, they have been the subjects of intensive management and research. Several studies have used broadscale acoustic telemetry arrays to study black sea bass movements at natural (Fabrizio et al, 2013(Fabrizio et al, , 2014 and artificial sites (Secor et al, 2019(Secor et al, , 2021Wiernicki et al, 2020); gag at natural sites (Ellis et al, 2019;Keller et al, 2020); red snapper at artificial sites (Topping and Szedlmayer, 2011;Curtis et al, 2015); greater amberjack at artificial sites (Jackson et al, 2018;Boyle et al, 2022a, b); and almaco jack at natural sites (Fontes et al, 2014;Gandra et al, 2020). However, despite intensive research and management, gag (SEDAR 71, 2021), red snapper (SEDAR 73, 2021), and black sea bass are currently overfished and experiencing overfishing (SEDAR 76, 2023).…”