The conservation of the endangered Mediterranean common dolphin (Delphinus delphis): Current knowledge and research priorities

1. Preservation of endangered species is now recognized as a relevant component of regional and global conservation actions achieved through the maintenance of the remaining populations in a favourable conservation status. The Mediterranean common dolphin (Delphinus delphis) is listed as an Endangered subpopulation in the International Union for Conservation of Nature Red List, with declining numbers in some of the areas where it has been studied for numerous years. Prey depletion, fisheries bycatch, pollution, health risks, and climate change are among the recognized threats that the species is facing in the region.
2. The existing national, regional, and international legislation pertinent to Mediterranean countries should aid greater science–policy–management integration and support innovative research and monitoring towards effective conservation. The challenges inherent in studying the pelagic D. delphis should not preclude the use of long-term, year-round, multiplatform surveys, side by side with the latest molecular tools, which aid our understanding of its populations' genetic diversity, resistance to diseases, and resilience in a semi-enclosed fast-changing sea.
3. Addressing the multiplicity of problems confronting the species requires collaborative effort at all levels to share and merge resources, data, and expertise more efficiently. In this review, we provide an overview of the current knowledge on the Mediterranean common dolphin, the main threats, and knowledge gaps that are priorities for addressing its conservation, while providing clear recommendations for effectively safeguarding the species and its habitat at both local and regional levels.

     

Conservation of transnational species: The tensions between legal requirements and best scientific evidence

1. This paper describes the tensions between the legal requirements for conservation and the most beneficial biological practice for mobile transnational marine species, using the harbour porpoise (Phocoena phocoena) in European Atlantic waters as a case study.
2. Harbour porpoise are the smallest and one of the most abundant cetaceans occurring throughout the European continental shelf waters, and are affected by human activities occurring in the same waters, especially certain fishing activities.
3. The Convention on the Conservation of European Wildlife and Natural Habitats (the Bern Convention) and its implementing legislation the Council Directive on the Conservation of Natural Habitats and of Wild Fauna and Flora 92/43/EEC (i.e. the Habitats Directive) are the main legal drivers for species conservation throughout the European Union. They aim for the long-term achievement of favourable conservation status and make provision for the use of two conservation measures: protected areas and strict protection measures. The strict protection measures aim to ensure that all forms of deliberate killing are prevented, and that where incidental killing and capture occurs, it does not have a negative effect on conservation status.
4. The conservation of harbour porpoise is currently dependent upon tackling the key issue of bycatch in fisheries. However, in challenges to Member States on their application of the Habitats Directive, the European Commission has chosen to focus on site designation rather than the implementation of the strict protection measures required to monitor and, where necessary, reduce bycatch.
5. This tension between a legal focus on the designation of protected areas instead of tackling threats such as bycatch has potentially led to negative conservation consequences for harbour porpoise and, in part, may explain why wider marine biodiversity has continued to deteriorate in Europe.

     

Seabird bycatch vulnerability to pelagic longline fisheries: Ecological traits matter

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Bottlenose dolphins (Tursiops truncatus) in the north-western Adriatic Sea: Spatial distribution and effects of trawling

1. Many species and populations of odontocetes have modified their behaviour to take advantage of feeding opportunities provided by fishing activities, with depredation of fishing gear being the most common type of adaptation.
2. The northern Adriatic Sea has been identified as an important marine mammal area because of a regular occurrence of common bottlenose dolphins. Boat surveys were conducted within a 3,000 km² sector of the Adriatic Sea off the coast of Veneto, Italy, between April and October 2018–2019. Based on 76 days at sea, 10,711 km of navigation, and 81 h 26 min of dolphin tracking, this study contributes novel quantitative information on dolphin spatial distribution, and on their occurrence in the wake of beam trawlers, otter trawlers, and midwater pair trawlers.
3. A combined generalized additive model and generalized estimation equation framework indicated that trawling—along with other physiographic, biological and anthropogenic variables—influenced dolphin distribution. In days of trawling, the chance of encountering dolphins increased by ~4.5 times (95% confidence interval 1.8–11.0) near active beam trawlers, by ~16.0 times (7.1–36.0) near otter trawlers, and by ~28.9 times (12.0–69.6) near midwater pair trawlers.
4. Spatial modelling was used to create maps of predicted distribution, suggesting differences in habitat use between trawling and no-trawling days. Spatial modelling for all days identified a dolphin distribution hotspot of 832 km², situated off the Po river delta.
5. Evidence contributed by this study can be used to inform management action within one of the world's areas most heavily impacted by fishing and other human encroachment. Such management action would help enforce the European Union's Habitats Directive and Marine Strategy Framework Directive, while also informing EU's Maritime Spatial Planning.

     

Genetic differentiation among Atlantic island populations of the brown spiny lobster Panulirus echinatus (Decapoda: Palinuridae)

1. Declines in Panulirus echinatus Smith, 1869 populations along their wide distribution in the Atlantic Ocean have spurred efforts to improve their fisheries management and conservation. In this study, the genetic structure of these populations is reported for the first time.
2. In a survey of 18 species‐specific polymorphic microsatellite markers, 152 individuals were genotyped from five Atlantic oceanic islands, covering most of the insular distribution range of the species. The analyses revealed that P. echinatus is genetically partitioned into two stocks in the Atlantic Ocean. A highly significant genetic structure was observed between north‐east and south‐west Atlantic populations based on fixation index, discriminant analysis of principal components, and structure and barrier analysis.
3. We suggest that the Equatorial Circulation System represents a biophysical barrier that effectively limits migration among Atlantic subtropical gyre systems, as has been described for other species. Other physical and ecological barriers, such as the Mid‐Atlantic Ridge itself, the distance between the eastern and western sides of the Atlantic (Mid‐Atlantic Barrier) and water mass differences, as well as other biological aspects, may also influence larval dispersal and modulate the insular distribution of this species.
4. The results show the existence of two distinct genetic stocks of P. echinatus and have implications for fisheries management in the Atlantic Ocean, including their independent management according to their individual status. The Cabo Verde and the Canarian populations (north‐east Atlantic) showed the lowest level of genetic variability in comparison with the south‐western populations. A combination of factors that have occurred or are occurring in the Canary Islands, such as overfishing and volcanic eruptions, is likely to explain the reduced abundance of this lobster species in the area.

     

Bycatch mortality can cause extirpation in four freshwater turtle species

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Whistle variability of the Mediterranean short beak common dolphin

1. The short-beaked common dolphin is a highly vocal species, with a wide distribution in all oceans, including the Mediterranean and the Black Seas. In the Mediterranean Sea, the short-beaked common dolphin inhabits both pelagic and neritic waters.
2. Osteological collections and the literature show that short-beaked common dolphins were widespread and abundant in much of the Mediterranean Sea until the late 1960s. During recent decades the species has declined in the whole basin, and, in 2003, it was listed as Endangered in the IUCN Red List.
3. Genetic studies strongly suggest that the Mediterranean and the Eastern North Atlantic populations are isolated from each other. Genetic differentiation within the Mediterranean Sea, between the Eastern Mediterranean (Ionian Sea) and Western Mediterranean populations, is also reported.
4. The aim of this study was to investigate the geographical variation in the characteristics of whistles of free-ranging short-beaked common dolphins living in the Mediterranean Sea, and to evaluate if whistle acoustic structure is the result of adaptation to local environment characteristics or of a possible genetic diversification.
5. Recordings were collected from 1994 to 2012 throughout the basin, employing multiple platforms. Twenty-six independent acoustic detections were made, and 704 whistles were extracted and considered for statistical analysis.
6. Whistle analysis enabled the identification of distinct geographical units of short-beaked common dolphin within the Mediterranean Sea. Genetic isolation is probably the major cause of the geographic variance of the Mediterranean short-beaked common dolphin whistle structure, which may reflect some evolutionary adaptations to particular ecological conditions or may be the by-product of morphological evolution.
7. The results of the present study show that intra-Mediterranean variability of whistle structure reflects the path of genetic studies, highlighting the possible use of acoustic data in combination with other sources of data (genetic, morphological, etc.) to identify geographic areas where discrete management units occur.

     

Characterization of seabird bycatch in eastern Canadian waters, 1998–2011, assessed from onboard fisheries observer data

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Use of remote sensing tools to predict focal areas for sea turtle conservation in the south-western Atlantic

1. Fisheries bycatch of non-target species in the commercial fleet is a major source of anthropogenic injury and mortality for sea turtles and marine megafauna.
2. The Río de la Plata maritime front (RLPMF) and its adjacent international waters – comprising part of the Argentine and Uruguayan exclusive economic zones, is a highly important fishing ground in the south-western Atlantic Ocean as well as feeding and development grounds for sea turtles.
3. This paper analyses the distribution of the bottom and pelagic trawling fishery within the RLPMF using information from Vessel Satellite Monitoring System. With this information, areas of highest trawling intensity were defined and further evaluated their overlap with sea turtle habitat-use areas from available sea turtle satellite tracking information.
4. Results besides identifying high-susceptibility areas for sea turtle bycatch by the commercial trawler fleet along the RLPMF, provide predictive tools to identify vulnerable areas to interaction of sea turtles and the commercial fishing fleet.
5. Implementation of bycatch mitigation measures, such as reduced fishing effort areas by the Argentine and Uruguayan fisheries management agencies has the potential to benefit the fisheries as well as marine megafauna. Furthermore, there is a need for additional research on the impact that this fleet can have on sea turtles present in the area.

     

Biodiversity,ecology, fisheries,and use and trade of Tetraodontiformes fishes reveal their socio‐ecological significance along the tropical Brazilian continental shelf

1. Tetraodontiformes fishes play a critical role in benthic and demersal communities and are facing threats due to anthropogenic impacts and climate change. However, they are poorly studied worldwide. To improve knowledge on the socio‐ecological significance and conservation of Tetraodontiformes a review of literature addressing the diversity, ecology, use and trade, conservation, and main threats of Tetraodontiformes combined with a comprehensive in situ dataset from two broad‐range multidisciplinary oceanographic surveys performed along the Tropical Brazilian Continental Shelf was undertaken.
2. Twenty‐nine species were identified, being primarily found on coral reefs and algal ecosystems. At these habitats, tetraodontids present highly diversified trophic categories and might play an important role by balancing the marine food web
3. Coral reef ecosystems, especially those near to the shelf break, seem to be the most important areas of Tetraodontiformes fishes, concentrating the highest values of species richness, relative abundance and the uncommon and Near Threatened species.
4. Ninety per cent of species are commonly caught as bycatch, being also used in the ornamental trade (69%) and as food (52%), serving as an important source of income for artisanal local fisheries.
5. Tetraodontiformes are threatened by unregulated fisheries, overexploitation, bycatch, and habitat loss due to coral reef degradation and the potential effects of climate change. These factors are more broadly impacting global biodiversity, food security, and other related ecosystem functions upon which humans and many other organisms rely.
6. We recommend the following steps that could improve the conservation of Tetraodontiformes along the tropical Brazilian Continental shelf and elsewhere: (i) data collection of the commercial, incidental, ornamental and recreational catches; (ii) improvement of the current legislation directed at the marine ornamental harvesting; (iii) increase efforts focused on the education and conservation awareness in coastal tourism and communities; and, most important, (iv) creation of marine reserves networks in priority areas of conservation, protecting either the species and key habitats for its survival.

     

A 40-year chronology of the vulnerability of spinetail devil ray (Mobula mobular) to eastern Pacific tuna fisheries and options for future conservation and management

1. Tuna fisheries are among the largest and most valuable fisheries in the world, but most interact with many non-target species, including several of high conservation importance. The spinetail devil ray (Mobula mobular) – listed as ‘Endangered’ on the IUCN Red List of Threatened Species – is a commonly discarded bycatch species, particularly in the eastern Pacific Ocean, yet insufficient data exist to undertake a traditional population assessment.
2. A new ecological risk assessment approach designed for data-limited settings – Ecological Assessment of the Sustainable Impacts of Fisheries (EASI-Fish) – was used to reconstruct the historical vulnerability status of M. mobular and to simulate potential changes in its status under 45 hypothetical conservation and management measures. These involved various temporal closures of the eastern Pacific Ocean tuna fishery, decreasing post-capture mortality by improved handling and release practices, and combinations of the two.
3. The species was classified as ‘Least Vulnerable’ between 1979 and 1993, but became ‘Most Vulnerable’ from 1994, which coincided with a rapid spatial expansion of the industrial purse-seine fishery, and especially from 2011 following the rapid increase in the number of sets made on floating objects. Simulating the conservation and management measures in place in 2018 revealed that 31 of the 45 scenarios resulted in a change in classification of the species to ‘Least Vulnerable’, which primarily involved a reduction of post-capture mortality by as little as 20%.
4. It is fortuitous in that education of fishers to implement appropriate best handling and release practices is simpler, more rapid and more cost-effective than the implementation of fishery closures or gear modifications, which can be expensive and complex to implement and monitor and will probably result in substantial reduction in the catches of target species.

     

The decline of short-beaked common dolphin (Delphinus delphis) in the waters off the island of Ischia (Gulf of Naples,Italy)

1. This study presents data on a local population of short-beaked common dolphin monitored in the waters off Ischia Island (Gulf of Naples, Italy) over a 16-year period (2000-2015). We examine dolphin occurrence and distribution and perform photoidentification analysis.
2. The data presented support the hypothesis that the waters around Ischia Island represent a feeding area, as well as a calving and an important nursery area for this local population, providing favourable conditions in which to give birth and raise calves.
3. The levelling-off of the photoidentification curves together with the continuous decline of the encounter rate lead us to believe that the area has been a hotspot for a local population (mainly resident) for years and that now this population is dying (has died) or is moving (has moved) to other locations.
4. Several expanding human activities at sea have the potential to impact on the common dolphin in the study area, the most significant possibly being habitat disturbance and degradation (including traffic and noise pollution) and overexploitation of food resources by the fishery.
5. The data presented in this study offer a strong argument for explicit and urgent population-specific conservation and management strategies to be developed and applied locally for common dolphins, considering that they rely on the region for important biological processes.

     

Dolphin population specialized in foraging with artisanal fishers requires zero-bycatch management to persist

1. The small population paradigm assumes that populations with low numbers of individuals intrinsically have a high probability of extinction. The small population of Lahille’s bottlenose dolphins Tursiops truncatus gephyreus that specializes in foraging with artisanal fishers in Laguna, southern Brazil, faces human pressures including bycatch in fishing gear. The viability of this population was modelled over 30 and 100 years under different levels of bycatch, including the current scenario of two bycatches every year, two scenarios with higher incidence of bycatches and three management scenarios. The sensitivity of predicted growth rates to fixed-proportion and observed-variation changes in life history parameters was explored.
2. The current scenario predicted a declining population (r = −0.014; λ = 0.986) with a high probability of extinction in the long term (PE = 0.71). A small increase in bycatches would result in a marked increase in the probability of extinction. Management scenarios seem promising, but only the zero-bycatch management scenario would make the difference between a declining and an increasing population.
3. As expected for slow-growing species, population growth rate was most sensitive to proportional changes in adult female and juvenile survival. However, considering observed variation in vital rates, population dynamics were most influenced by variation in reproductive rates.
4. To determine the highest priority for management action, another simulation was made of how additional threat scenarios of recognized human activities (i.e. bycatch influencing adult survival and increased underwater noise or pollution influencing calf survival) would affect population dynamics. Population growth rate was very sensitive to changes in adult bycatch (especially females), as expected, and only subtly sensitive to a reduction in calf survival.
5. The current level of bycatch is unsustainable. Bycatch needs to be eliminated to maximize the probability of long-term persistence of this dolphin population. However, this population’s persistence could be threatened by natural variation in reproductive rates.

     

Potential distribution and population trends of the smalltail shark Carcharhinus porosus inferred from species distribution models and historical catch data

1. Updated distribution ranges are crucial for conservation status assessments. Comprehensive analyses combining published literature and available data on historical catches and species distribution models (SDMs) are effective tools that could improve the prediction of more realistic scenarios for some species, especially those with limited information available and facing multiple threats.
2. The present study aimed at generating an updated distribution for the smalltail shark Carcharhinus porosus, one of the most threatened and understudied shark species of the western Atlantic Ocean. Estimates of the key areas for this species conservation based on the SDMs, and trends in catch probabilities throughout its distribution range are provided.
3. Four algorithms (BIOCLIM, Domain, Mahalanobis, and Maximum Entropy) were used to model the distribution of C. porosus and calculate its habitat suitability based on marine environmental variables. To assess historical catch probability trends, we built a generalized linear model from published and grey literature data. This analysis was used to estimate catch probability as an indication of population trends.
4. SDMs suggest that the northern coast of South America (NCSA) harbours the most suitable habitats for C. porosus in the world, which was expected given its historically high catch rate in this region. In addition, there was a continuously declining catch probability trend starting in the 1970s. However, the decline was smaller for the NCSA as compared with the Gulf of Mexico and the eastern South America coast.
5. Results indicate that the NCSA should be considered the currently most important area in the world for this species conservation. Furthermore, the lack of data throughout Central and South American marine regions hampers the evaluation of extinction risk throughout its updated distribution. Thus, research in these areas is urgently required for a more comprehensive conservation status assessment.

     

Determining spatial use of the world's second largest humpback dolphin population: Implications for place‐based conservation and management

1. Place‐based management can be an effective conservation tool to protect cetaceans from anthropogenic pressures. The spatial use of the world's second largest population of the threatened Indo‐Pacific humpback dolphins (Sousa chinensis) is not well‐documented, which makes it challenging to designate protected areas for this population.
2. To address this knowledge gap and to test the efficacy of an existing dolphin protected area (Zhanjiang Leizhou Bay Municipal Humpback Dolphin Nature Reserve, ZLBMHDNR), boat‐based surveys were conducted to document dolphin occurrence from 2015 to 2018, covering an area of 1221 km² in the eastern waters off Zhanjiang, China. In total, 253 dolphin group sightings were obtained during 174 survey days.
3. Spatial analysis showed that humpback dolphins aggregated in three core‐use areas with higher sighting density within the survey area. Furthermore, intermediate‐use and broad‐use areas were identified that could be essential for the movements of humpback dolphins among these core‐use areas.
4. The spatial usage of humpback dolphins was compared inside and outside the ZLBMHDNR. Results suggest that the ZLBMHDNR is insufficient to encompass a significant portion of dolphin habitat. The ZLBMHDNR (21 km²) is not large enough, and thus it should be expanded for effective place‐based conservation management in this region.
5. For developing a protected area network, important dolphin habitats identified in this study should be protected as a single management unit. Additionally, mitigation of anthropogenic pressures is needed to be taken into consideration as conservation initiatives in the study area.
6. This study provides support for a more science‐informed protected area network, and highlights the necessity of implementing place‐based conservation and management for the world's second largest humpback dolphin population.

     

Are bycatch rates sufficient as the principal fishery performance measure and method of assessment for seabirds?

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Beware of changes: Conservation of Indo‐Pacific humpback dolphins in disturbed habitats

1. Protecting critical habitats of the Indo‐Pacific humpback dolphin, Sousa chinensis, is a hot topic of discussion for marine biodiversity conservation in China and many Southeast Asian countries. In practice, sound habitat protection action (HPA) planning often suffers from information gaps in macroscopic habitat configurations and changes in the habitat conditions of humpback dolphins.
2. Recent publications in the journal Aquatic Conservation: Marine and Freshwater Ecosystems (AQC) have served to advance humpback dolphin conservation in Chinese waters by resolving such habitat configurations and indicating significant changes in distribution patterns and habitat characteristics under intense coastal anthropogenic activity.
3. We highlight an integrative research framework to investigate habitat configuration and long‐term habitat changes when planning a holistic HPA programme for humpback dolphins. When constructing habitat configuration baselines, field surveys should be designed and conducted in a systematic manner to ensure survey efforts cover diverse environments equally, in either a spatially stratified or gridded pattern, to minimize potential spatial sampling biases. Long‐term habitat changes can be revealed by comparing satellite images from different decades. Changes in habitat preferences and habitat characteristics can be explored through questionnaire surveys on local ecological knowledge, associating historical occurrences with coastline features and projecting historical habitat configuration by species distribution modelling exercises.
4. A lack of good communication and sharing of information between research and management sectors can still be an obstacle to the implementation of sound conservation practices, however, even though there is robust scientific evidence to fill knowledge gaps in distribution and habitat baselines. We have addressed the need to establish a mechanism to improve and streamline information sharing between research teams, management sectors, and stakeholder groups.

     

Catch and trade bans for seahorses can be negated by non-selective fisheries

1. All seahorse species (genus Hippocampus) are listed under Schedule I of India's Wild Life Protection Act, making all capture and trade of seahorses illegal. In the more than 15 years since the ban, little work has been done to assess its effects on seahorse conservation.
2. Between 2015 and 2017, fisheries and trade surveys were conducted along the south-east coast of India, in the state of Tamil Nadu, historically known to be a hub for seahorse catches and trade.
3. Seahorses were primarily landed as bycatch, although in greater quantities by traditional drag nets than as trawl bycatch. Total annual catches were estimated between 4.98 million and 13.64 million seahorses, 87% of which were caught by active non-selective gear.
4. Generalized additive models revealed that seahorse catch per unit effort had non-linear relations with depth and latitude, and were higher in biogenic habitats, with active, bottom-used, and non-selective gears (e.g. trawls).
5. The illegal nature of the trade in seahorses hampered an understanding of trade routes and trade volumes. Catch estimates indicated that 11.21–30.31 tonnes of seahorses probably entered trade, yet interviews with traders only documented trade of about 1.6 tonnes.
6. Fishers reported a decreasing availability of seahorses. Since most seahorses come from bycatch in persistent fisheries that are not directly affected by the ban on seahorse capture, this decline is likely to represent a population decline.
7. A fishery and trade ban for incidentally caught species, particularly in a poorly regulated fishery, appears to add little conservation value. There needs to be a shift in the management approach, moving from a ban towards spatial and temporal restrictions, and toward enforcing existing fishery regulations.

     

Science and conservation of Amazonian crocodilians: a historical review

1. Crocodilians represent one of the oldest extant vertebrate lineages. They have co-existed with humans throughout the Amazon basin for thousands of years, often having a strong cultural and economic influence on people's lives. Shifts in the socio-economic and political reality of the Amazon basin during the last century have led crocodilian populations to face large variations in their numbers according to different levels of exploitation and strategies for their conservation.
2. This article reviews the scientific knowledge obtained between 1945 and 2019 on the biology, conservation and management for the four Amazonian crocodilian (caiman) species (Caiman crocodilus, Melanosuchus niger, Paleosuchus palpebrosus and Paleosuchus trigonatus). It provides a general overview on past and current population status and research efforts involving caimans in the Amazon basin and discusses perspectives for the future.
3. The most significant studies on the ecology, genetics and management strategies are examined in more detail and this information is contextualized to provide an overview of the most relevant findings that might explain caiman population trends over the last 75 years.
4. Systems for sustainable management in the Amazon basin have been discussed for the past 20 years, but remain rarely applicable. It is necessary to develop new ways to maintain healthy caiman populations through innovative management programmes. Sustainable harvesting of wildlife has been shown to promote conservation targets, especially those initiatives based on community co-management. In this article, we propose some general guidelines for future management schemes, in the expectation that the information provided by the scientific community will be considered fully without political agendas determining the priorities.

     

Freshwater turtle bycatch research supports science‐based fisheries management

1. Although it is sometimes difficult for researchers to ensure that their work is used by resource managers to make informed decisions, an example where this knowledge–action gap has been breached is in research published in Aquatic Conservation: Marine and Freshwater Ecosystems (AQC) – among other journals – that has assisted fisheries managers in identifying strategies for reducing freshwater turtle bycatch in commercial hoop net fisheries in Ontario, Canada.
2. Research published in AQC has provided evidence towards a simple and effective method for preventing turtle bycatch mortality in hoop nets, which could be adopted by the fishers. Other research published in AQC evaluated the effect of bycatch mortality on the probability of persistence of turtle populations with population viability analyses, and outlined the need to minimize bycatch mortality to prevent local extirpation. Nine other papers have been published on freshwater turtle bycatch in Ontario, furthering our knowledge on this issue including seasonality and temperature effects on catches, other net modifications, post‐release effects and assisted recovery, and the perspectives of fishers.
3. The research results were presented to local resource managers with further discussions involving industry and stakeholders to minimize turtle bycatch mortality. Over several years, researchers have provided information to resource managers; however, when an incident of high turtle mortality caught the public eye, the research was readily available and changes in regulations were quick to occur.
4. Reasonably good communication among researchers, resource managers, industry, stakeholders, and the broader public allowed the rapid implementation of regulations to mitigate freshwater turtle bycatch mortality and bridged the knowledge–action gap between researchers and resource managers.
5. Both articles published in AQC had practical conservation impacts and were influential in providing local resource managers with feasible solutions, and the impetus to change regulations. These impacts extended to other jurisdictions and their monitoring programmes, where methods to reduce turtle bycatch mortality were also implemented.