Rapid shifts in distribution and high‐latitude persistence of oceanographic habitat revealed using citizen science data from a climate change hotspot

Abstract

The environmental effects of climate change are predicted to cause distribution shifts in many marine taxa, yet data are often difficult to collect. Quantifying and monitoring species' suitable environmental habitats is a pragmatic approach for assessing changes in species distributions but is underdeveloped for quantifying climate change induced range shifts in marine systems. Specifically, habitat predictions present opportunities for quantifying spatiotemporal distribution changes while accounting for sources of natural climate variation. Here we demonstrate the utility of a marine-based habitat model parameterized using citizen science data and remotely sensed environmental covariates for quantifying shifts in oceanographic habitat suitability over 22 years for a coastal-pelagic fish species in a climate change hotspot. Our analyses account for the effects of natural intra- and interannual climate variability to reveal rapid poleward shifts in core (94.4 km/decade) and poleward edge (108.8 km/decade) oceanographic habitats. Temporal persistence of suitable oceanographic habitat at high latitudes also increased by approximately 3 months over the study period. Our approach demonstrates how marine citizen science data can be used to quantify range shifts, but necessitates shifting focus from species distributions directly, to the distribution of species' environmental habitat preferences.

Marine recreational fishing and the implications of climate change

“…For many species, migration patterns are tied to prevailing currents, and the duration that preferred environmental conditions are present in particular regions can facilitate or hinder the movements of many pelagic and coastal species that are fished recreationally (Briscoe et al, ). Yellowtail kingfish ( Seriola lalandi, Carangidae) for example is a species caught in eastern Australian fisheries, where the recreational catch exceeds that of the commercial catch (Lowry, Molony, Keag, & Penney, ), and where the distribution of oceanographic habitat has rapidly shifted poleward over the past 20 years (Champion, Hobday, Tracey, & Pecl, ). In the south‐east region of Australia, several “new” highly prized recreational species have been recorded, including mahi mahi or dolphin fish ( Coryphaena hippurus, Coryphaenidae), yellowtail kingfish, snapper and others, creating some excitement among recreational fishers ().…”

“…Since the increase in yellowtail kingfish numbers in southern Australia, local charter operators in Tasmania have started advertising for fishing trips (Pecl et al, ). The poleward range extension of yellowtail kingfish (Champion, Hobday, Tracey, et al, ; Robinson et al, ) means that fishers and managers will need to adapt to these changes in future. Marine resource users require information relevant to their activities at decision‐making timescales in order to adapt effectively.…”

Oceanographic habitat suitability is positively correlated with the body condition of a coastal‐pelagic fish

“…This species is targeted in several eastern Australian fisheries, where the estimated annual recreational catch exceeds the average annual commercial catch (Henry & Lyle, ; Lowry, Molony, Keag, & Penney, ). Recent analyses have revealed that the distribution of oceanographic habitat for kingfish from eastern Australia has rapidly shifted poleward over the past 20 years (Champion, Hobday, Tracey, et al, ). These analyses are supported by photo‐verified observations of kingfish poleward of their historic southern Australian range boundary recorded by the Range Extension Database and Mapping Project (Redmap; http://www.redmap.org.au; Pecl, Stuart‐Smith, et al, ) and a rapid assessment of species that are likely to be undergoing poleward range extensions in south‐eastern Australia (Robinson, Gledhill, et al, ).…”

“…These occurrence records were combined with 20,000 pseudo‐absence points randomly generated throughout the study area to categorize unsuitable environmental habitat for kingfish, thus providing a binomial response variable for statistical modelling. Twenty thousand pseudo‐absences were selected to (a) ensure that environmental variability occurring over the spatiotemporal extent encompassed by the occurrence dataset was adequately captured, (b) comply with Barbet‐Massin, Jiguet, Albert, and Thuiller () who recommend selecting a large number (i.e.> 10,000) of pseudo‐absences when using regression techniques to develop species distribution models, and (c) facilitate comparisons with habitat suitability models for other pelagic fishes from eastern Australia (see Champion, Hobday, Tracey, et al, ) that were also developed using approximately 20,000 pseudo‐absences (e.g. Brodie et al () and Hill et al () who used 20,000 and 23,242 pseudo‐absences, respectively).…”

“…Species distribution or habitat suitability models have become valuable tools for assessing spatiotemporal variation in environmental habitat quality (Brodie et al, ; Hazen et al, ). These models have been successfully applied to predict the seasonal distributions of coastal‐pelagic fishes (Brodie et al, ) and to identify shifts in their core (Dell, Wilcox, Matear, Chamberlain, & Hobday, ; Hill, Tobin, Reside, Pepperell, & Bridge, ) and range edge habitats under global change (Champion, Hobday, Tracey, & Pecl, ; Robinson, Hobday, Possingham, & Richardson, ). While predictions created using habitat suitability models are commonly dependent on the probability of species occurrence (Robinson et al, ), these predictions may also be used to provide novel insights into the physiological status of individuals across broad spatial extents.…”