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Barrett TJ, Rossong MA, van den Heuvel MR, Munkittrick KR. Assessing reproductive effects on fish populations: an evaluation of methods to predict the reproductive strategy of fishes. ENVIRONMENTAL MONITORING AND ASSESSMENT 2020; 192:613. [PMID: 32875407 DOI: 10.1007/s10661-020-08580-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 08/25/2020] [Indexed: 06/11/2023]
Abstract
Many environmental monitoring programs include an assessment of the health of fish populations using a sentinel species and include an indicator of reproductive potential. Knowledge of the reproductive strategy of the fish species is critical for data interpretation but is not always known. The reproductive strategy of a species can be determined from detailed histological analyses of ovaries throughout the reproductive cycle; however, these studies can be costly and can delay the implementation of a monitoring program. Three quick and cost-effective methods of predicting the reproductive strategy (annual single spawning or annual multiple spawning) are evaluated in this study using predicted probabilities from binary logistic regression models as a means of classifying the reproductive strategies of 18 different fish species in Atlantic Canada. The first method was based on the hypothesis that the variability in the ovary weight-body weight relationship in prespawning females is higher in multiple spawners. This method did not have a good classification rate due to some multiple spawners having low variability. The other two methods involved predictor variables representing the proportion of oocytes in different stages of development and predictor variables representing the distribution of oocyte sizes during the prespawning season for 111 fish (25 different samples for species). Predicted probabilities from these regression models could be used to correctly classify the reproductive strategies of all 25 samples (development stage model) and all but one sample (oocyte size distribution model). These models can be used to estimate the reproductive strategy of a species from a single sample of fish collected during the prespawning period to support species selection and data interpretation in environmental monitoring programs.
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Affiliation(s)
- Timothy J Barrett
- Department of Biology, University of New Brunswick, Saint John, NB, E2L 4L5, Canada.
| | - Melanie A Rossong
- Department of Biology, University of Prince Edward Island, Charlottetown, PE, C1A 4P3, Canada
- Department of Biology and Ocean Sciences Centre, Memorial University of Newfoundland, St. John's, NL, A1C 5S7, Canada
| | - Michael R van den Heuvel
- Department of Biology, University of Prince Edward Island, Charlottetown, PE, C1A 4P3, Canada
- Canadian Rivers Institute, University of Prince Edward Island, Charlottetown, PE, C1A 4P3, Canada
| | - Kelly R Munkittrick
- Department of Biology, University of New Brunswick, Saint John, NB, E2L 4L5, Canada
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Coffin MRS, Courtenay SC, Pater CC, van den Heuvel MR. An empirical model using dissolved oxygen as an indicator for eutrophication at a regional scale. MARINE POLLUTION BULLETIN 2018; 133:261-270. [PMID: 30041313 DOI: 10.1016/j.marpolbul.2018.05.041] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 05/20/2018] [Accepted: 05/22/2018] [Indexed: 06/08/2023]
Abstract
Simple empirical models can sometimes capture salient patterns without sacrificing predictive capacity when compared to more complex models. Herein we examine dissolved oxygen as an indicator of eutrophication status for shallow estuaries. Dissolved oxygen was measured hourly in the upper estuary of 15 watersheds along a nutrient-loading and geographic gradient. Metrics describing hypoxia and supersaturation were devised and then analyzed using multivariate statistics. Results revealed independent responses for hypoxia and supersaturation with hypoxia-related metrics correlating strongly with water residence. A metric integrating hypoxia and supersaturation effectively discriminated between seagrass and algae-dominated habitats and was significantly correlated with both water residence and nitrate-N loading. Chlorophyll, measured bi-weekly, was not correlated with our predictor variables likely because it does not account for benthic production. Over 70% of the variability in hypoxia was explained by water residence and nitrate-N loading indicating that this model can be of use for managers.
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Affiliation(s)
- Michael R S Coffin
- Fisheries and Oceans Canada, Gulf Fisheries Center, 343 Université Av., Moncton, New Brunswick, Canada; Canadian Rivers Institute, Department of Biology, University of Prince Edward Island, Charlottetown, Canada.
| | - Simon C Courtenay
- Canadian Rivers Institute, Department of Biology, University of Prince Edward Island, Charlottetown, Canada; Canadian Rivers Institute, School of Environment, Resources and Sustainability, University of Waterloo, Waterloo, Canada
| | - Christina C Pater
- Canadian Rivers Institute, Department of Biology, University of Prince Edward Island, Charlottetown, Canada
| | - Michael R van den Heuvel
- Canadian Rivers Institute, Department of Biology, University of Prince Edward Island, Charlottetown, Canada
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Baker DGL, Eddy TD, McIver R, Schmidt AL, Thériault MH, Boudreau M, Courtenay SC, Lotze HK. Comparative analysis of different survey methods for monitoring fish assemblages in coastal habitats. PeerJ 2016; 4:e1832. [PMID: 27018396 PMCID: PMC4806602 DOI: 10.7717/peerj.1832] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 03/01/2016] [Indexed: 11/20/2022] Open
Abstract
Coastal ecosystems are among the most productive yet increasingly threatened marine ecosystems worldwide. Particularly vegetated habitats, such as eelgrass (Zostera marina) beds, play important roles in providing key spawning, nursery and foraging habitats for a wide range of fauna. To properly assess changes in coastal ecosystems and manage these critical habitats, it is essential to develop sound monitoring programs for foundation species and associated assemblages. Several survey methods exist, thus understanding how different methods perform is important for survey selection. We compared two common methods for surveying macrofaunal assemblages: beach seine netting and underwater visual census (UVC). We also tested whether assemblages in shallow nearshore habitats commonly sampled by beach seines are similar to those of nearby eelgrass beds often sampled by UVC. Among five estuaries along the Southern Gulf of St. Lawrence, Canada, our results suggest that the two survey methods yield comparable results for species richness, diversity and evenness, yet beach seines yield significantly higher abundance and different species composition. However, sampling nearshore assemblages does not represent those in eelgrass beds despite considerable overlap and close proximity. These results have important implications for how and where macrofaunal assemblages are monitored in coastal ecosystems. Ideally, multiple survey methods and locations should be combined to complement each other in assessing the entire assemblage and full range of changes in coastal ecosystems, thereby better informing coastal zone management.
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Affiliation(s)
- Duncan G L Baker
- Department of Biology, Dalhousie University , Halifax, Nova Scotia , Canada
| | - Tyler D Eddy
- Department of Biology, Dalhousie University , Halifax, Nova Scotia , Canada
| | - Reba McIver
- Department of Biology, Dalhousie University , Halifax, Nova Scotia , Canada
| | - Allison L Schmidt
- Department of Biology, Dalhousie University , Halifax, Nova Scotia , Canada
| | | | - Monica Boudreau
- Fisheries and Oceans, Gulf Fisheries Centre , Moncton, New Brunswick , Canada
| | - Simon C Courtenay
- Fisheries and Oceans, Gulf Fisheries Centre, Moncton, New Brunswick, Canada; University of Waterloo, Canadian Rivers Institute, Waterloo, Ontario, Canada
| | - Heike K Lotze
- Department of Biology, Dalhousie University , Halifax, Nova Scotia , Canada
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Barrett TJ, Brasfield SM, Carroll LC, Doyle MA, van den Heuvel MR, Munkittrick KR. Reproductive strategies and seasonal changes in the somatic indices of seven small-bodied fishes in Atlantic Canada in relation to study design for environmental effects monitoring. ENVIRONMENTAL MONITORING AND ASSESSMENT 2015; 187:305. [PMID: 25925154 DOI: 10.1007/s10661-015-4496-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 04/01/2015] [Indexed: 06/04/2023]
Abstract
Small-bodied fishes are more commonly being used in environmental effects monitoring (EEM) studies. There is a lack of understanding of the biological characteristics of many small-bodied species, which hinders study designs for monitoring studies. For example, 72% of fish population surveys in Canada's EEM program for pulp and paper mills that used small-bodied fishes were conducted outside of the reproductive period of the species. This resulted in an inadequate assessment of the EEM program's primary effect endpoint (reproduction) for these studies. The present study examined seasonal changes in liver size, gonad size, and condition in seven freshwater and estuarine small-bodied fishes in Atlantic Canada. These data were used to examine differences in reproductive strategies and patterns of energy storage among species. Female gonadal recrudescence in all seven species began primarily in the 2-month period in the spring before spawning. Male gonadal development was concurrent with females in five species; however, gonadal recrudescence began in the fall in male three-spined stickleback (Gasterosteus aculeatus) and slimy sculpin (Cottus cognatus). The spawning period for each species was estimated from the decline in relative ovary size after its seasonal maximum value in spring. The duration of the spawning period reflected the reproductive strategy (single vs multiple spawning) of the species. Optimal sampling periods to assess reproductive impacts in each species were determined based on seasonal changes in ovary size and were identified to be during the prespawning period when gonads are developing and variability in relative gonad size is at a minimum.
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Affiliation(s)
- Timothy J Barrett
- Canadian Rivers Institute, Department of Biology, University of New Brunswick, Saint John, NB, E2L 4L5, Canada,
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