Foraging, bioenergetic and predation constraints on diel vertical migration: field observations and modelling of reverse migration by young‐of‐the‐year herring Clupea harengus

Abstract

Diel vertical migration (DVM) of young-of-the-year (YOY) herring Clupea harengus and one of their major predators, pikeperch Sander lucioperca, was examined using bottom-mounted hydroacoustics in Himmerfjärden, a brackish bay of the Baltic Sea, in summer. In contrast to previous studies on DVM of C. harengus aggregated across size and age classes, YOY C. harengus showed a reverse DVM trajectory, deeper at night and, on average, shallower during the day. This pattern was observed consistently on five acoustic sampling occasions in 3 years and was corroborated by two out of three trawl surveys. Large acoustic targets (target strength >-33 dB, probably piscivorous S. lucioperca >45 cm) showed a classic DVM trajectory, shallow at night and deeper during the day. Variability in YOY C. harengus vertical distribution peaked at dawn and dusk, and their vertical distribution at midday was distinctly bimodal. This reverse DVM pattern was consistent with bioenergetic model predictions for YOY C. harengus which have rapid gut evacuation rates and do not feed at night. Reverse DVM also resulted in low spatial overlap with predators.

Partial migration in fishes: definitions, methodologies and taxonomic distribution

“…In addition, mature C. harengus do not migrate to spawn each year [skipped breeding partial migration (Engelhard & Heino, 2005)]. Finally, young‐of‐the‐year (YOY) C. harengus also display a bimodal vertical distribution and can hence also be classified as exhibiting partial DVM (Jensen et al , 2011). This example highlights the complexity evident in migratory and movement patterns in fishes in the wild, which (unfortunately for ichthyologists) defies neat and exclusive categorization.…”

Inverse vertical migration and feeding in glacier lanternfish (Benthosema glaciale)

“…IDVM has commonly been ascribed to zooplankton species avoiding NDVM predators (Ohman et al 1983, Ohman 1990; Lagergren et al 2008). It has been described for fish (Neilson and Perry 1990), although rarely (Jensen et al 2011), and has only recently been documented in mesopelagic fishes (Kaartvedt et al 2009). …”

Seasonal changes in partial, reverse diel vertical migrations of cisco Coregonus artedi

“…It is speculated that a portion of the population was willing to take these greater risks to obtain food only during summer, when zooplankton density and foraging potential near the surface was highest compared to the other seasons. Similar partial migrations have been observed for reverse migrating C. harengus during summer, when they perform a low risk, low reward and high risk, high reward migration strategy (Jensen et al ., ). In winter, C. artedi did not migrate vertically, probably because there were low risk, low reward conditions present throughout the water column due to darkness below the snow (>25 cm) and thick ice cover (>75 cm).…”

“…For example, reverse DVM of cisco Coregonus artedi Lesueur 1818 seems to be related to the type and amount of prey resources available between temperate lakes (Ahrenstorff et al ., ). Similarly, reverse migrations have been observed for kokanee salmon Oncorhynchus nerka (Walbaum 1792) and Baltic herring Clupea harengus L. 1758 when predation risk is high, deeper in the water column during the day (Stockwell & Johnson, ; Jensen et al ., ). Even more rarely examined in the literature is partial DVM, where portions of a population perform normal or reverse DVM while others do not migrate (Mehner, ).…”

“…Jensen et al . () documented a partial, reverse DVM of young‐of‐the‐year C. harengus and hypothesized that this behaviour could be linked to low risk, low reward and high risk, high reward conditions present in the water column. Therefore, it was predicted that partial migrations may result when individual fitness may be maximized in different ways depending on individual state ( e.g .…”