Biocomplexity in Pacific herring (Clupea pallasii) of Puget Sound, USA

Small-scale genetic and demographic diversity can stabilize populations on a larger scale. However, subpopulations of pelagic fish species can be difficult to distinguish. Here, we examine demographic diversity in 21 stocks of Pacific herring (Clupea pallasii) in Puget Sound, USA using a multivariate auto-regressive state-space (MARSS) model, and data from both acoustic surveys paired with trawls, and subtidal egg surveys to estimate population growth trends. Herring populations associated with individual spawning beaches are asynchronous, but share a common negative growth rate across the Puget Sound estuary. We found that both survey techniques observe the same underlying demographic processes, and that egg surveys are a more accurate estimator of total spawning biomass. We used states obtained from MARSS analysis to measure portfolio effects in Puget Sound herring, and found that the Puget Sound population as a whole is stabilized by the presence of several separate spawning subpopulations. Available environmental data was not sufficient to explain variations in spawning biomass; however, herring may respond to spawning site conditions that aren’t currently measured

Age truncation and portfolio effects in Puget Sound Pacific herring

Forage fish undergo dramatic changes in abundance through time. Long-term fluctuations, which have historically been attributed to changes in recruitment, may also be due to changes in adult mortality. Pacific herring, a lightly exploited forage fish in Puget Sound, WA, have exhibited shifts in age structure and decreases in spawning biomass during the past 30 years. Here, we investigate changes in adult mortality as a potential explanation for these shifts. Using a hierarchical, age-structured population model, we indicate that adult natural mortality for Puget Sound Pacific herring has increased since 1973. We find that natural mortality has increased for every age class of adult (age 3+), especially age 4 fish, whose estimated mortality has doubled over the survey time period (from M=0.84 to M=1.76). We demonstrate that long-term shifts in mortality explain changes in age structure, and may explain biomass declines and failure to reach management thresholds for some spawning sites in Puget Sound. Temporal shifts in natural adult mortality could have negative implications for herring and herring predators. For predators, these implications include a reduction in the stability of the herring resource

Pengembangan Media Pembelajaran Matematika Berbantu Wondershare dengan Pendekatan Rme pada Materi SMP

Pemilihan media pembelajaran yang kurang tepat dapat membuat siswa kurang antusias terhadap mata pelajaran matematika. Sehingga banyak siswa yang mendapat nilai dibawah KKM. Solusinya dibutuhkan media pembelajaran yang menarik serta dapat menumbuhkan antusias siswa dalam belajar.Penelitian ini bertujuan untuk mengembangkan media pembelajaran berbantu wondershare dengan pendekatan RME sehingga menghasilkan media yang layak dan efektif digunakan selama pembelajaran. Jenis penelitian ini adalah penelitian Research and Development dengan menggunakan model pengembangan ADDIE, terdiri dari 5 tahapan yaitu analisis, design, developmen, implementasi, evaluasi.Sebelum diimplementasikan, media pembelajaran terlebih dahulu dilakukan uji validasi oleh ahli media, ahli materi serta angket tanggapan siswa. Hasil validasi ahli tersebut berkriteria sangat baik sehingga media pembelajaran layak untuk digunakan.Pembelajaran dengan media pembelajaran berbantu wondershare dengan pendekatan RME efektif digunakan oleh peserta didik. Hal ini di buktikan dari rata rata kelas eksperimen dan kontrol yaitu 82,03 dan 60,54. Ketuntasan belajar individu kelas ekperimen terdapat 31 siswa tuntas dari 36 siswa, dan kelas kontrol terdapat 8 siswa tuntas dari 27 siswa. Dilihat dari ketuntasan belajar klasikal siswa untuk kelas kontrol dan eksperimen sebesar 22,86% dan 86,11%. Dengan analisis menggunakan uji t pihak kanan diperoleh nilaiyaitu 9,607>1,667 maka H0 ditolak, jadi pembelajaran dengan menggunakan media pembelajaran berbantuan wondershare dengan pendekatan RME lebih baik dibandingkan dengan pembelajaran konvensional pada materi SMP

Robustness of potential biological removal to monitoring, environmental, and management uncertainties

Support for this project was provided by the Lenfest Ocean Program.The potential biological removal (PBR) formula used to determine a reference point for human-caused mortality of marine mammals in the United States has been shown to be robust to several sources of uncertainty. This study investigates the consequences of the quality of monitoring on PBR performance. It also explores stochastic and demographic uncertainty, catastrophic events, sublethal effects of interactions with fishing gear, and the situation of a marine mammal population subject to bycatch in two fisheries, only one of which is managed. Results are presented for two pinniped and two cetacean life histories. Bias in abundance estimates and whether there is a linear relationship between abundance estimates and true abundance most influence conservation performance. Catastrophic events and trends in natural mortality have larger effects than environmental stochasticity. Managing only one of two fisheries with significant bycatch leads, as expected, to a lower probability of achieving conservation management goals, and better outcomes would be achieved if bycatch in all fisheries were managed. The results are qualitatively the same for the four life histories, but estimates of the probability of population recovery differ.Publisher PDFPeer reviewe

Estimating bycatch mortality for marine mammals : concepts and best practices

Support for this project was provided by the Lenfest Ocean Program (Contract ID: #31008).Fisheries bycatch is the greatest current source of human-caused deaths of marine mammals worldwide, with severe impacts on the health and viability of many populations. Recent regulations enacted in the United States under the Fish and Fish Product Import Provisions of its Marine Mammal Protection Act require nations with fisheries exporting fish and fish products to the United States (hereafter, “export fisheries”) to have or establish marine mammal protection standards that are comparable in effectiveness to the standards for United States commercial fisheries. In many cases, this will require estimating marine mammal bycatch in those fisheries. Bycatch estimation is conceptually straightforward but can be difficult in practice, especially if resources (funding) are limiting or for fisheries consisting of many, small vessels with geographically-dispersed landing sites. This paper describes best practices for estimating bycatch mortality, which is an important ingredient of bycatch assessment and mitigation. We discuss a general bycatch estimator and how to obtain its requisite bycatch-rate and fisheries-effort data. Scientific observer programs provide the most robust bycatch estimates and consequently are discussed at length, including characteristics such as study design, data collection, statistical analysis, and common sources of estimation bias. We also discuss alternative approaches and data types, such as those based on self-reporting and electronic vessel-monitoring systems. This guide is intended to be useful to managers and scientists in countries having or establishing programs aimed at managing marine mammal bycatch, especially those conducting first-time assessments of fisheries impacts on marine mammal populations.Publisher PDFPeer reviewe

Estimating the abundance of marine mammal populations

Support for this project was provided by the Lenfest Ocean Program.Motivated by the need to estimate the abundance of marine mammal populations to inform conservation assessments, especially relating to fishery bycatch, this paper provides background on abundance estimation and reviews the various methods available for pinnipeds, cetaceans and sirenians. We first give an “entry-level” introduction to abundance estimation, including fundamental concepts and the importance of recognizing sources of bias and obtaining a measure of precision. Each of the primary methods available to estimate abundance of marine mammals is then described, including data collection and analysis, common challenges in implementation, and the assumptions made, violation of which can lead to bias. The main method for estimating pinniped abundance is extrapolation of counts of animals (pups or all-ages) on land or ice to the whole population. Cetacean and sirenian abundance is primarily estimated from transect surveys conducted from ships, small boats or aircraft. If individuals of a species can be recognized from natural markings, mark-recapture analysis of photo-identification data can be used to estimate the number of animals using the study area. Throughout, we cite example studies that illustrate the methods described. To estimate the abundance of a marine mammal population, key issues include: defining the population to be estimated, considering candidate methods based on strengths and weaknesses in relation to a range of logistical and practical issues, being aware of the resources required to collect and analyze the data, and understanding the assumptions made. We conclude with a discussion of some practical issues, given the various challenges that arise during implementation.Publisher PDFPeer reviewe

Third workshop on appropriate sampling schemes for protected, endangered and threatened species bycatch (WKPETSAMP3)

The workshops WKPETSAMP2 and WKPETSAMP3 were convened following a special request from the European Union’s Directorate-General for Environment (DG ENV) on appropriate sampling schemes for endangered, threatened and protected (ETP) species. In particular, these workshops were tasked with providing concrete inputs and results to inform ICES advice to DG ENV on ‘appropriate bycatch monitoring systems at Member State level and on regional coordination’. An aim of the PETSAMP workshops was to generate improved insights into how aspects of sampling design may impact the precision and accuracy of bycatch estimates and the detection probability of bycatch events. The workshop considered key issues such as: how sampling coverage (percentage of monitored fishing operations) impacts the precision of bycatch estimates and how this is dependent on the bycatch probability (how often a bycatch is encountered); if stratification improves precision and if this is dependent on bycatch probability; if it is better to sample few vessels but many trips (e.g. typical of reference fleets and Electronic Monitoring programmes) or many vessels but fewer trips (e.g. typical of at-sea observer programmes). To do this the WKPETSAMP2 extended the simulation framework (SCOTI) developed by WGBYC in 2022. This framework was used in WKPETSAMP3 and was parameterized with data from several case studies. The case studies are from ongoing or historical sampling programs and represent different waters across Europe and different fisheries

Invasive mangrove removal and recovery : food web effects across a chronosequence

M.S. University of Hawaii at Manoa 2012.Includes bibliographical references.Red mangrove (Rhizophora mangle) was introduced to Hawaiʻi in 1902 and has since overgrown many coastal areas in Hawaiʻi, transforming nearshore sandy habitat into heavily vegetated areas with low water velocity, high sedimentation rates, and anoxic sediments. Mangrove forests provide habitat for exotic species, including burrowing predators, which can exert top-down effects on benthic communities. Removal of mangrove overstory is a popular management technique; here we use infauna community structure, crab catch data, and a cage experiment performed over a chronosequence of removals from 2007-2010 to show that overstory removal causes gradual changes in community composition, that community shifts are concurrent with a slow decomposition of sedimentary mangrove biomass (k = 5.6 ! 10-4 ± 0.9 ! 10-4 d-1), and that burrowing predators do not have significant effects on the infaunal community where R. mangle is intact or where it has been removed. Changes over time after removal include an increase in total infaunal abundance, a decrease in sub-surface deposit feeders, and an increase in suspension-feeding worms. Burrowing crab densities are uniform across mangrove and removal sites, and do not affect infaunal communities as they do in native mangroves. These results show that recovery from invasion and removal occurs gradually and is not governed by top-down effects

Implications of demographic diversity for forage fish, their fisheries, and ecosystems

Thesis (Ph.D.)--University of Washington, 2017-12Forage fish play a key role in marine ecosystems and fisheries worldwide. They are highly productive, and undergo dramatic fluctuations in productivity, which interact with fishing pressure and spatial dynamics to generate population variability. The mechanisms and demographic processes behind this variability are poorly understood, creating a challenge for fishery managers. In this dissertation, I address the implications of demographic diversity for forage fish ecology and management. I investigate demographic diversity in space (Chapter 1) in space and time (Chapter 2), and among different forage species (Chapters 3 and 4). In the first chapter, I demonstrate that spatial diversity in a largely unfished forage fish population (Puget Sound Pacific herring; Clupea pallasii) can generate portfolio effects, which stabilize their availability as prey. In the second chapter, I build a hierarchical model to address the potential processes behind these portfolio effects, distinguishing temporal variation in mortality from spatial differences, and demonstrating that adult mortality has led to age truncation and recruitment-dominated dynamics. In the third chapter, I develop an age-structured population model and use a management strategy evaluation framework to show that demographic diversity among forage fish species (specifically, for sardine, anchovy, and menhaden-like forage species) affects management outcomes and tradeoffs. In the final chapter, I use a time series approach to investigate asynchronous dynamics in sardine (Sardinops spp.) and anchovy (Engraulis spp.), and show that although these two species are often viewed as alternating members of the forage fish guild, sardine and anchovy alone do not compose a forage portfolio that buffers fisheries and food webs from dramatic shifts in productivity. These results demonstrate the rarity of asynchronous dynamics and the importance of considering, but not relying upon, demographic diversity in forage fish populations