Utilizing individual fish biomass and relative abundance models to map environmental niche associations of adult and juvenile targeted fishes

Many fishes undergo ontogenetic habitat shifts to meet their energy and resource needs as they grow. Habitat resource partitioning and patterns of habitat connectivity between conspecific fishes at different life-history stages is a significant knowledge gap. Species distribution models were used to examine patterns in the relative abundance, individual biomass estimates and environmental niche associations of different life stages of three iconic West Australian fishes. Continuous predictive maps describing the spatial distribution of abundance and individual biomass of the study species were created as well predictive hotspot maps that identify possible areas for aggregation of individuals of similar life stages of multiple species (i.e. spawning grounds, fisheries refugia or nursery areas). The models and maps indicate that processes driving the abundance patterns could be different from the body size associated demographic processes throughout an individual's life cycle. Incorporating life-history in the spatially explicit management plans can ensure that critical habitat of the vulnerable stages (e.g. juvenile fish, spawning stock) is included within proposed protected areas and can enhance connectivity between various functional areas (e.g. nursery areas and adult populations) which, in turn, can improve the abundance of targeted species as well as other fish species relying on healthy ecosystem functioning

Climate impact on Italian fisheries (Mediterranean Sea)

Global warming is increasingly affecting marine ecosystems and ecological services they provide. One of the major consequences is a shift in species geographical distribution, which may affect resources availability to fisheries. We computed the mean temperature of the catch (MTC) for Italian catches from 1972 to 2012 to test if an increase of warmer-water species against colder-water ones was observed. We further analysed the relationship among MTC, landings, fishing effort and climatic factors through a Linear Mixed Models approach. Global MTC increased at a rate of 0.12 _C per decade. Though, by considering the influence of sea surface temperature (SST), a strongest increase (0.31 _C) was estimated in southernmost areas, while in the northernmost basin (Northern Adriatic Sea) a decrease of 0.14 _C was observed. SST resulted the most relevant driver, and the relationship between MTC and SST showed a high spatial variability both in terms of strength and sign, being positively stronger in southernmost areas while negative in the northernmost basin. The result is probably underestimated since several psychrophilous and thermophilous species were not included in the analysis. However, it seems that a change towards warmer-water species has already occurred in Italian marine ecosystems. Conversely, total landings temporal dynamics seem mostly driven by changes in fishing effort rather than by MTC and climatic factors. Consequently, fishery management strategies need to focalize primarily on fishing effort reduction, in order to reduce the pressure on the stocks while increasing their resilience to other stressors, among which global warmingGlobal warming is increasingly affecting marine ecosystems and ecological services they provide. One of the major consequences is a shift in species geographical distribution, which may affect resources availability to fisheries. We computed the mean temperature of the catch (MTC) for Italian catches from 1972 to 2012 to test if an increase of warmer-water species against colder-water ones was observed. We further analysed the relationship among MTC, landings, fishing effort and climatic factors through a Linear Mixed Models approach. Global MTC increased at a rate of 0.12 A degrees C per decade. Though, by considering the influence of sea surface temperature (SST), a strongest increase (0.31 A degrees C) was estimated in southernmost areas, while in the northernmost basin (Northern Adriatic Sea) a decrease of 0.14 A degrees C was observed. SST resulted the most relevant driver, and the relationship between MTC and SST showed a high spatial variability both in terms of strength and sign, being positively stronger in southernmost areas while negative in the northernmost basin. The result is probably underestimated since several psychrophilous and thermophilous species were not included in the analysis. However, it seems that a change towards warmer-water species has already occurred in Italian marine ecosystems. Conversely, total landings temporal dynamics seem mostly driven by changes in fishing effort rather than by MTC and climatic factors. Consequently, fishery management strategies need to focalize primarily on fishing effort reduction, in order to reduce the pressure on the stocks while increasing their resilience to other stressors, among which global warming

A Net Energy Analysis of the Global Agriculture, Aquaculture, Fishing and Forestry System

The global agriculture, aquaculture, fishing and forestry (AAFF) energy system is subject to three unsustainable trends: (1) the approaching biophysical limits of AAFF; (2) the role of AAFF as a driver of environmental degradation; and (3) the long-term declining energy efficiency of AAFF due to growing dependence on fossil fuels. In response, we conduct a net energy analysis for the period 1971–2017 and review existing studies to investigate the global AAFF energy system and its vulnerability to the three unsustainable trends from an energetic perspective. We estimate the global AAFF system represents 27.9% of societies energy supply in 2017, with food energy representing 20.8% of societies total energy supply. We find that the net energy-return-on-investment (net EROI) of global AAFF increased from 2.87:1 in 1971 to 4.05:1 in 2017. We suggest that rising net EROI values are being fuelled in part by ‘depleting natures accumulated energy stocks’. We also find that the net energy balance of AAFF increased by 130% in this period, with at the same time a decrease in both the proportion of rural residents and also the proportion of the total population working in AAFF—which decreased from 19.8 to 10.3%. However, this comes at the cost of growing fossil fuel dependency which increased from 43.6 to 62.2%. Given the increasing probability of near-term fossil fuel scarcity, the growing impacts of climate change and environmental degradation, and the approaching biophysical limits of global AAFF, ‘Odum’s hoax’ is likely soon to be revealed

Economic development and coastal ecosystem change in China

Despite their value, coastal ecosystems are globally threatened by anthropogenic impacts, yet how these impacts are driven by economic development is not well understood. We compiled a multifaceted dataset to quantify coastal trends and examine the role of economic growth in China's coastal degradation since the 1950s. Although China's coastal population growth did not change following the 1978 economic reforms, its coastal economy increased by orders of magnitude. All 15 coastal human impacts examined increased over time, especially after the reforms. Econometric analysis revealed positive relationships between most impacts and GDP across temporal and spatial scales, often lacking dropping thresholds. These relationships generally held when influences of population growth were addressed by analyzing per capita impacts, and when population density was included as explanatory variables. Historical trends in physical and biotic indicators showed that China's coastal ecosystems changed little or slowly between the 1950s and 1978, but have degraded at accelerated rates since 1978. Thus economic growth has been the cause of accelerating human damage to China's coastal ecosystems. China's GDP per capita remains very low. Without strict conservation efforts, continuing economic growth will further degrade China's coastal ecosystems.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000340593000007&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Multidisciplinary SciencesSCI(E)[email protected]