Globally coordinated acoustic aquatic animal tracking reveals unexpected, ecologically important movements across oceans, lakes and rivers

Acoustic telemetry is a popular approach used to track many different aquatic animal taxa in marine and freshwater systems. However, information derived from focal studies is typically resource- and geography-limited by the extent and placement of acoustic receivers. Even so, animals tagged and tracked in one region or study may be detected unexpectedly at distant locations by other researchers using compatible equipment, who ideally share that information. Synergies through national and global acoustic tracking networks are facilitating significant discoveries and unexpected observations that yield novel insight into the movement ecology and habitat use of wild animals. Here, we present a selection of case studies that highlight unexpected tracking observations or absence of observations where we expected to find animals in aquatic systems around the globe. These examples span freshwater and marine systems across spatiotemporal scales ranging from adjacent watersheds to distant ocean regions. These unexpected movements showcase the power of collaborative telemetry networks and serendipitous observations. Unique and unexpected observations such as those presented here can capture the imagination of both researchers and members of the public, and improve understanding of movement and connectivity within aquatic ecosystems

The devil in the deep: Expanding the known habitat of a rare and protected fish

The accepted geographic range of a species is related to both opportunity and effort in sampling that range. In deepwater ecosystems where human access is limited, the geographic ranges of many marine species are likely to be underestimated. A chance recording from baited cameras deployed on deep uncharted reef revealed an eastern blue devil fish (Paraplesiops bleekeri) at a depth of 51 m and more than 2 km further down the continental shelf slope than previously observed. This is the first verifiable observation of eastern blue devil fish, a protected and endemic southeastern Australian temperate reef species, at depths greater than the typically accepted depth range of 30 m. Knowledge on the ecology of this and many other reef species is indeed often limited to shallow coastal reefs, which are easily accessible by divers and researchers. Suitable habitat for many reef species appears to exist on deeper offshore reefs but is likely being overlooked due to the logistics of conducting research on these often uncharted habitats. On the basis of our observation at a depth of 51 m and observations by recreational fishers catching eastern blue devil fishes on deep offshore reefs, we suggest that the current depth range of eastern blue devil fish is being underestimated at 30 m. We also observed several common reef species well outside of their accepted depth range. Notably, immaculate damsel (Mecaenichthys immaculatus), red morwong (Cheilodactylus fuscus), mado (Atypichthys strigatus), white-ear (Parma microlepis) and silver sweep (Scorpis lineolata) were abundant and recorded in a number of locations at up to a depth of at least 55 m. This underestimation of depth potentially represents a large area of deep offshore reefs and micro habitats out on the continental shelf that could contribute to the resilience of eastern blue devil fish to extinction risk and contribute to the resilience of many reef species to climate change

Developing management goals and associated assessment methods for Sweden’s nationally managed fish stocks : a project synthesis

This report summarizes and synthesizes results from the Swedish Agency of Marine and Water Management (SwAM, or HaV) funded project “Förvaltningsmål för nationella arter (Management goals for nationally managed species)”. The objectives of the project have been to promote the development of management goals and associated status assessment methods and indicators, as well as reference points, for some nationally managed fish stocks both in coastal as well as freshwater areas. The report focusses largely on species and stocks that can be defined as data-poor. Such stocks are characterised by marked limitations in data availability and/or resources allocated to detailed analytical stock projections. Data-poor stocks also often lack carefully formulated management goals and associated methods and indicators for assessing stock status. In this report, we provide an overview of potential assessment methods and indicators and try to synthesise how they work and what the strengths and weaknesses are by applying them to selected data poor stocks such as pikeperch, pike, whitefish, and vendace. We also discuss how they relate to different potential management goals and provide recommendations for their application. We grouped the indicators and assessment methods by the three categories that are now used in the yearly status assessment framework provided by SLU Aqua (Resursöversikten/Fiskbarometern) – i) mortality, ii) abundance/biomass and iii) size/age structure. The results are also described for these three main categories of assessment indicators. Included is also a status report from a size- and age-based population dynamics model (Stock Synthesis 3) that is being developed for pikeperch in Lake Hjälmaren.An important experience from the project is that to improve the assessment methods for Swedish national fish stocks, it is important that managers develop both general as well as more detailed quantitative goals for the individual stocks. This should ideally be conducted in various forms of collaboration with the main stakeholders and scientists involved with assessment as participatory processes foster legitimacy. Carefully articulated management goals, which are possible to translate into quantitative targets, will facilitate the development of various approaches and methods to monitor stock statuses. Given the strong and complex interactions of fish and their environments it is also important to consider other pressures than fisheries when developing indicators and assessment methods.Our synthesis highlights a number of areas where the assessment of data-poor stocks can be improved:1. Apply precautionary principles for data-limited stocks, particularly ones that are known to be vulnerable to exploitation.2. Tailor approaches to how fisheries are managed in Sweden. Swedish nationally managed fish stocks are not managed by quotas (with one exception, vendace in the Bothnian Bay) and do not aim for maximum sustainable yield. Instead, the coastal and inland fisheries are managed by regulating the effort in the small-scale commercial fisheries (number of fishers/licenses and amount of gear). Regulation of recreational and subsistence fisheries effort, in terms of licenses or number of fishers) is not applied, nor possible since the fisheries is lacking obligatory notification and reporting systems. All national fisheries, however, are regulated by various technical measures (closed areas, size-limits, bag-limits, gear restrictions etc). Thus, goals and assessment methods that result in harvest limits or quota recommendations expressed in e.g. biomass/numbers are difficult to use as basis for management. Instead, there is a need for alternative management goals and associated assessment methods.3. Use best practice methods and indicators and adapt as scientific knowledge is developed. Data-limited methods are developing rapidly, and new methods/approaches are proposed in the scientific literature every year. It is thus important to be updated on the most recent developments. 4. Clearly describe limitations/assumptions of methods used. It is important to be aware of and critically evaluate the assumptions underlying the analyses, and to carefully communicate uncertainty together with the stock status assessment.5. Be particularly careful with low sample numbers. Many indicators and methods can be applied also on small sample sizes, however, the accuracy and precision of the estimates risk being low in such cases.6. Accept that there is no "gold standard" for fisheries assessment. Each case study is unique and needs to be balanced against data availability, local needs and other important factors. This also means that analysts need to be careful when using generic reference levels or “borrowing” data from other stocks.7. If possible, use several different methods/indicators. Although several indicators aim to measure similar aspects of the stock, small methodological differences can support the overall interpretation of individual indicator values. It is particularly important to incorporate many aspects and indicators (size/age/abundance/mortality) in order to produce a balanced assessment.8. Develop means of communication. Indicators and goals should be easy to understand. However, interpretation of results from multi-indicator frameworks can be challenging. There is thus a need for finding ways of communication that can convey complicated results in a simple-to-understand manner.9. For details on additional improvements, we refer the reader to the sub-header “recommendations for the future” found under each chapter.The implementation of Stock Synthesis for pikeperch in Lake Hjälmaren showed that it is possible to develop a more ambitious and detailed stock assessment model for a relatively data-poor stock. The model results partly support earlier interpretations of the development of the stock and the importance of the changes in regulations in 2001 (increased minimum size, increased mesh size and reduced mortality of undersized pikeperch). Before the model can be implemented and used for practical management, a number of actions for improvement are needed, which are highlighted in the relevant chapter. The most important next step is establishing management goals and reference levels for this stock. We recommend that such a dialogue is initiated by managers. The fisheries management goals should consider both biomass, fisheries mortality and size-based targets.To conclude, we stress the importance of improving all ongoing aspects related to the assessments of data-poor Swedish stocks. Strong local stocks and sustainable fisheries are vital for a variety of fisheries-related businesses and practices, particularly in rural areas, providing economical and societal value. Fishes also have important roles in aquatic food-webs and it is important that ecological values are managed wisely in order to reach targets for water quality, ecosystem structure and diversity. Given the strong and complex interactions of fish and their environments it is also important to consider other pressures than fisheries when developing indicators and assessment methods

Active acoustic tracking suggests that soft sediment fishes can show site attachment: a preliminary assessment of the movement patterns of the blue-spotted flathead (Platycephalus caeruleopunctatus)

Background It is generally considered that on relatively homogenous marine soft sediment habitats, such as sand, fish are unlikely to show site attachment. This poses challenges for management and the evaluation of the efficacy of marine protected areas, in which soft sediments often make up more than 70 % of habitats. The blue-spotted flathead is a commercially and recreationally targeted species found on soft sediments in coastal marine waters of south-eastern Australia. There are no published data on its movement patterns. Here, using active acoustic telemetry, we aim to (a) quantify movement and habitat use of blue-spotted flathead, (b) compare area usage to no-take sanctuary zone size and (c) obtain data to aid in the design of a large passive receiver array to be used in long-term comprehensive tracking of soft sediment fish. Results Three of five blue-spotted flathead that were tagged exhibited strong site attachment and were detected close to their release points for the entire 60-day study period. The two other fish were not detected after 4 and 25 days and were likely to have moved out of the study area (search radius ≈ 3 km). For the three fish tracked over 60 days, the area used was compact (mean ± SE = 0.021 km2 ± 0.037) and two patterns of movement were apparent: (1) a small activity space used in its entirety each day (two fish) and (2) a larger activity space in which a separate area is utilised each day (one fish). Conclusions Our study is the first to document the movement of blue-spotted flathead, and these preliminary results demonstrate two broad movement patterns shown by this species on soft sediments in Jervis Bay. Over the course of 60 days, a majority of fish in this study showed strong site attachment; however, a number of fish also made larger-scale movements. Finally, our study suggests that a tightly spaced, passive acoustic array would provide meaningful results for this species, although strategically placed receivers outside this array would be required to detect any longer range movements

AquaticVID: a low cost, extended battery life, plug-and-go video system for aquatic research

AquaticVID is a low-cost, long battery life video camera system for use in a wide-range of aquatic research applications. The system can be deployed for multiple day recording on a single charge, is submersible to depths of down to 950 m and can be constructed quickly using easily sourced off-the-shelf materials. The system is essentially ‘plug-and-go’, as assembly and preparation for deployment take

AquaticVID: a low cost, extended battery life, plug-and-go video system for aquatic research

AquaticVID is a low-cost, long battery life video camera system for use in a wide-range of aquatic research applications. The system can be deployed for multiple day recording on a single charge, is submersible to depths of down to 950 m and can be constructed quickly using easily sourced off-the-shelf materials. The system is essentially ‘plug-and-go’, as assembly and preparation for deployment takes < 30 minutes without the need for technical build or programming skills. All of the electrical components are interchangeable with parts from multiple manufacturers and the camera system can be adapted to fit a variety of waterproof enclosure sizes depending on power and data storage requirements. Here, we describe three versions of the AquaticVID in detail and give examples of above and below water research undertaken with the system. The small size and extended battery times, coupled with ease of use and low cost (US$ 268–540) make the AquaticVID a useful option for numerous aquatic research applications

Kunskapsunderlag för ekosystembaserad havsförvaltning i Bottenhavet

Ekosystembaserad havsförvaltning anges som ett viktigt verktyg för att nå Sveriges miljömål. Denna rapport tar ett första steg i riktning mot ett vetenskapligt underlag för att stödja ekosystembaserad havsförvaltning i ett pilotområde i södra Bottenhavet. Ekosystemkomponenter (dvs. arter och livsmiljöer) som är viktiga för modellering av ekosystemet identifieras och deras status samt faktorer som påverkar dem redovisas. Även kunskapsluckor kopplade till påverkansfaktorer diskuteras, samt hur dessa påverkansfaktorer integreras med ekosystemkomponenterna, liksom vilka ekosystemtjänster som ekosystemkomponenterna bidrar till. Många av ekosystemkomponenterna har inte god miljöstatus, särskilt grunda bottnar som har ett högt exploateringstryck. Oroväckande nog saknas det övervakning av både grunda kustnära mjukbottnar och utsjöbankar, fastän dessa områden är av intresse för exploatering samtidigt som de har hög biodiversitet och är kopplade till många ekosystemtjänster. Dock finns det en del data tillgängligt i området som kan användas vid modellering för att ta fram kartor över ekosystemkomponenter och även ekosystemtjänster, som kan vara viktiga underlag för ekosystembaserad förvaltning i södra Bottenhavet. I flera fall är kunskapen om belastningar i södra Bottenhavet och hur de kopplar till statusen av ekosystemkomponenter relativt god, men det saknas information om kumulativa effekter av påverkansfaktorer. Många av de marina arter som finns längst in i Östersjön lever här vid sin nordliga utbredningsgräns, vilket kan innebära att de är extra känsliga för mänskliga belastningar och klimatförändring. Storskaligt fiske efter strömming i utsjön och dess effekter på strömmingsbestånden kan påverka ekosystemets funktion. Strömmingen är talrik och spelar en stor roll i södra Bottenhavets ekosystem. Eftersom strömming vandrar mellan utsjön och kusten kan den koppla samman näringsvävar i kust och utsjö. I Bottenhavets område kan man se tydliga intressekonflikter gällande resursförvaltning. Traditionella lokala näringar baserar sig mycket på fiske av strömming och laxfisk, men vikande fångster av den mer storvuxna strömming som fiskas för humankonsumtion, liksom av laxfisk, skapar problem för det kustnära yrkesfisket. Här finns en uppenbar konkurrenssituation både med det storskaliga pelagiska fisket i utsjön och med naturliga predatorer. Dessa konflikter är svåra att lösa med de förvaltningsmetoder som används idag. Södra Bottenhavets ekosystem skulle sannolikt gynnas av en mer helhetsbaserad förvaltning av fiskbestånden och livsmiljöer, utifrån samtliga faktorer som påverkar dem. I kustområdet gäller detta även, inte minst, de områden där gösens och sikens status är mycket svag, liksom viktiga områden för rekrytering av gädda. En sådan mer helhetsbaserad förvaltning innefattar en samplanering av fiskeregleringar, skyddade områden och åtgärder för att restaurera och skydda diverse livsmiljöer. Förbättring av livsmiljöer för fisk förväntas även gynna andra delar av den biologiska mångfalden och ekosystemtjänster, inklusive olika arters motståndskraft och förmåga att anpassa sig till pågående klimatförändringar

Long-term effects of no-take zones in Swedish waters

Marine protected areas (MPAs) are increasingly established worldwide to protect and restore degraded ecosystems. However, the level of protection varies among MPAs and has been found to affect the outcome of the closure. In no-take zones (NTZs), no fishing or extraction of marine organisms is allowed. The EU Commission recently committed to protect 30% of European waters by 2030 through the updated Biodiversity Strategy. Importantly, one third of these 30% should be of strict protection. Exactly what is meant by strict protection is not entirely clear, but fishing would likely have to be fully or largely prohibited in these areas. This new target for strictly protected areas highlights the need to evaluate the ecological effects of NTZs, particularly in regions like northern Europe where such evaluations are scarce. The Swedish NTZs made up approximately two thirds of the total areal extent of NTZs in Europe a decade ago. Given that these areas have been closed for at least 10 years and can provide insights into long-term effects of NTZs on fish and ecosystems, they are of broad interest in light of the new 10% strict protection by 2030 commitment by EU member states.In total, eight NTZs in Swedish coastal and offshore waters were evaluated in the current report, with respect to primarily the responses of focal species for the conservation measure, but in some of the areas also ecosystem responses. Five of the NTZs were established in 2009-2011, as part of a government commission, while the other three had been established earlier. The results of the evaluations are presented in a synthesis and also in separate, more detailed chapters for each of the eight NTZs. Overall, the results suggest that NTZs can increase abundances and biomasses of fish and decapod crustaceans, given that the closed areas are strategically placed and of an appropriate size in relation to the life cycle of the focal species. A meta-regression of the effects on focal species of the NTZs showed that CPUE was on average 2.6 times higher after three years of protection, and 3.8 times higher than in the fished reference areas after six years of protection. The proportion of old and large individuals increased in most NTZs, and thereby also the reproductive potential of populations. The increase in abundance of large predatory fish also likely contributed to restoring ecosystem functions, such as top-down control. These effects appeared after a 5-year period and in many cases remained and continued to increase in the longer term (>10 years). In the two areas where cod was the focal species of the NTZs, positive responses were weak, likely as an effect of long-term past, and in the Kattegat still present, recruitment overfishing. In the Baltic Sea, predation by grey seal and cormorant was in some cases so high that it likely counteracted the positive effects of removing fisheries and led to stock declines in the NTZs. In most cases, the introduction of the NTZs has likely decreased the total fishing effort rather than displacing it to adjacent areas. In the Kattegat NTZ, however, the purpose was explicitly to displace an unselective coastal mixed bottom-trawl fishery targeting Norway lobster and flatfish to areas where the bycatches of mature cod were smaller. In two areas that were reopened to fishing after 5 years, the positive effects of the NTZs on fish stocks eroded quickly to pre-closure levels despite that the areas remained closed during the spawning period, highlighting that permanent closures may be necessary to maintain positive effects.We conclude from the Swedish case studies that NTZs may well function as a complement to other fisheries management measures, such as catch, effort and gear regulations. The experiences from the current evaluation show that NTZs can be an important tool for fisheries management especially for local coastal fish populations and areas with mixed fisheries, as well as in cases where there is a need to counteract adverse ecosystem effects of fishing. NTZs are also needed as reference for marine environmental management, and for understanding the effects of fishing on fish populations and other ecosystem components in relation to other pressures. MPAs where the protection of both fish and their habitats is combined may be an important instrument for ecosystembased management, where the recovery of large predatory fish may lead to a restoration of important ecosystem functions and contribute to improving decayed habitats.With the new Biodiversity Strategy, EUs level of ambition for marine conservation increases significantly, with the goal of 30% of coastal and marine waters protected by 2030, and, importantly, one third of these areas being strictly protected. From a conservation perspective, rare, sensitive and/or charismatic species or habitats are often in focus when designating MPAs, and displacement of fisheries is then considered an unwanted side effect. However, if the establishment of strictly protected areas also aims to rebuild fish stocks, these MPAs should be placed in heavily fished areas and designed to protect depleted populations by accounting for their home ranges to generate positive outcomes. Thus, extensive displacement of fisheries is required to reach benefits for depleted populations, and need to be accounted for e.g. by specific regulations outside the strictly protected areas. These new extensive EU goals for MPA establishment pose a challenge for management, but at the same time offer an opportunity to bridge the current gap between conservation and fisheries management

The Ecology of Temperate Soft Sediment Fishes: Implications for Fisheries Management and Marine Protected Area Design

Marine protected areas (MPAs) are an increasingly common management approach to assist in conserving marine biodiversity by limiting, avoiding or removing anthropogenic activities such as pollution, habitat destruction and fishing. Globally, a considerable proportion of the area under protection in MPAs comprises soft sediments. Research on rocky reefs and coral reefs has demonstrated that when MPAs are well designed and implemented, the abundance and biomass of targeted fish species can increase. However, demersal fish on marine soft sediments have been poorly studied and it remains unclear whether they respond in the same ways to protection as fish on other habitats. In this thesis, I aimed to assess (i) whether MPA protection in south-east Australia has affected the species composition, abundance and size of demersal marine soft sediment fishes among management zones and (ii) the degree of long-term residency shown by a key recreationally and commercially targeted species in relation to MPA size and zoning. First, I used baited remote underwater videos (BRUVs) to sample the fish assemblages and test hypotheses about the effects of MPA management and implementation. My results revealed that in, shallow (10 m), deep (20 m) and offshore (50–60 m) waters, the demersal soft sediment fish assemblages were characterised by a few frequently occurring species. At all depths sampled the most common species were flathead (Platycephalus caeruleopunctatus & Platycephalus grandispinis). Shallow- and deepwater BRUV sampling was carried out between May and June in 2011, 2013 and 2015, within Jervis Bay Marine Park. At the assemblage level, no impact of MPA zoning was detected at either depth. There was also no difference between zones in total relative abundance (abundance of all species combined) or species richness at either depth. Abundances of individual species (those appearing on ≥ 25% of BRUVS samples) were also compared between zones; In shallow-water, there was a 32% greater abundance of Platycephalus spp. in no-take zones (NTZs) compared to partially protected areas (PPAs) over the study. In addition, abundances were more stable in NTZs across time. In shallow-water, Eastern fiddler ray (Trygonorrhina fasciata) and shovelnose ray (Aptychotrema rostrata), also had higher abundances in NTZs compared to PPAs in 2015. In deep-water there were no differences between zones for any individual species. There were no differences in length of flathead between zones at either depth. Offshore comparisons were carried out between August 3 and December in 2015, within Jervis Bay Marine Park, Batemans Marine Park and open access (OA) areas outside the two MPAs. Assemblages showed clear differences among NTZ, PPA, and fished OA areas. At the species level, on average, larger individuals of longspine flathead (P. grandispinis) were observed in NTZs than in both PPAs and OAs. There were also substantially higher abundances of ocean jackets (Nelusetta ayraudi) in NTZs. In offshore water there were no differences in abundances among zones for any other species or in species richness and total relative abundance. Second, I tested the assumption that fish on soft sediments are unlikely to show residency by evaluating the movement patterns of the bluespotted flathead (P. caeruleopunctatus) in Jervis Bay Marine Park. Bluespotted flathead were acoustically tagged within a NTZ in spring 2014 (n=25), autumn 2015 (n=15), and summer 2015 (n=6). I then monitored the tagged fish for 625 days. Bluespotted flathead exhibited small-scale and long-term residency within the NTZ. Over the first 108 days post tagging most fish (74%) remained within a ~200 ha area of NTZ and were detected frequently. I observed residency of up to 600 days. Although close to two thirds of the tagged fish were only detected within Jervis Bay, the remainder were detected moving up to 155 km from where they were tagged. Generally, these fish had a prolonged period of site residency before making these large-scale movements. Importantly, range testing confirmed that acoustic tags in this habitat were detected with a high degree of confidence and reliability. My findings demonstrate that temperate demersal fishes found on marine soft sediments can be influenced by protection within MPAs at a number of spatial scales. However, the response is highly variable among species with the majority showing no response, a relatively small effect size for those that do show a response and assemblage wide responses occurring in offshore waters but not within nearshore waters. In conclusion, marine soft sediments are an extensive habitat that harbour a unique demersal fish community. This habitat supports an important component of marine biodiversity and represents a rich fishery resource. This study provides a rare example of MPA effects on demersal soft sediment assemblages and presents substantial evidence of long-term residency by a demersal soft sediment associated fish within an NTZ