@article{brooks_alpizar-jara_pollock_steffen_pack_norman_2002, title={An online wild turkey population dynamics model}, volume={30}, number={1}, journal={Wildlife Society Bulletin}, author={Brooks, E. N. and Alpizar-Jara, R. and Pollock, K. H. and Steffen, D. E. and Pack, J. C. and Norman, G. W.}, year={2002}, pages={41–45} } @article{brooks_2002, title={Using reproductive values to define optimal harvesting for multisite density-dependent populations: example with a marine reserve}, volume={59}, ISSN={["1205-7533"]}, DOI={10.1139/F02-058}, abstractNote={ A new method for determining optimal harvest from age-structured populations with a density-dependent stock-recruit relationship is presented. The theoretical optimal harvest comes from removing the age-class with the smallest ratio of reproductive value to weight. The method is derived from considering the sensitivity of equilibrium egg production to harvest using results for density-dependent Leslie matrices. The method holds in both single- and multi-site contexts and is derived for both Ricker and Beverton–Holt recruitment functions. I illustrate the method for a one-site model of Arcto-Norwegian cod (Gadus morhua) and obtain the same optimal strategy as previous methods, namely that age-class 6 should be harvested 45%. Including age-specific selectivities, the best constrained yields occur at a harvest rate of 11% on ages 5–12. This yield is 73% of the theoretical optimum. I considered the same model when a reserve is established and found that high transfer rates out of the reserve (where spawners attain a higher fecundity) produced greater yields that were 86% of the one-site (no reserve) yield. Also, if overfishing occurs at 1.5 and 2.0 times the optimal level in the one-site case, then most yields from the reserve model are greater than those from the one-site model. }, number={5}, journal={CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES}, author={Brooks, EN}, year={2002}, month={May}, pages={875–885} } @article{alpizar-jara_brooks_pollock_steffen_pack_norman_2001, title={An eastern wild turkey population dynamics model for Virginia and West Virginia}, volume={65}, ISSN={["0022-541X"]}, DOI={10.2307/3803093}, abstractNote={Hunting can have potentially significant impacts on wild turkey (Meleagris gallopavo) populations. We developed a 2-sex Leslie-type matrix model that predicts wild turkey population size for spring-summer and fall-winter periods to understand the effects of hunting on the dynamics of wild turkey populations in Virginia and West Virginia. A base model incorporates parameters derived from a large-scale radiotelemetry study (n = 1,543 hens radio-tagged) conducted over areas with different fall hunting seasons in Virginia and West Virginia from 1989 to 1994. These data made it possible to evaluate the effects of season length, season timing, and 1- versus 2-sex kills on population growth and future harvests. A sensitivity analysis confirmed that fall hunting has the strongest negative effect on the population growth rate. For the range of parameters explored, population growth rate appeared to decrease linearly with increases in fall hunting. Also, the proportion of males in the population was more sensitive to fall rather than spring hunting. These results were invariant to a wide variety of different model calibrations.}, number={3}, journal={JOURNAL OF WILDLIFE MANAGEMENT}, author={Alpizar-Jara, R and Brooks, EN and Pollock, KH and Steffen, DE and Pack, JC and Norman, GW}, year={2001}, month={Jul}, pages={415–424} } @article{brooks_pollock_hoenig_hearn_1998, title={Estimation of fishing and natural mortality from tagging studies an fisheries with two user groups}, volume={55}, ISSN={["1205-7533"]}, DOI={10.1139/cjfas-55-9-2001}, abstractNote={We present generalizations of fishery models that allow for the separate estimation of fishing mortality when more than one user group is present (e.g., a commercial and a recreational fishery). This model also allows for the fisheries to be in operation for any length of time whereas previously fisheries were generally considered to be pulse or continuous. Three cases are considered: (i) fisheries operate consecutively, (ii) fisheries overlap for a part of their seasons, and (iii) fisheries are in operation for the whole year. The results of a simulation study are included, which provide estimates of fishing and natural mortality along with their proportional standard errors (CVs). All scenarios had good precision, with most CVs < 25% and usually very little difference between the three cases. Coefficients of interaction, the potential gain by one fishery if another is closed down, are also given along with a method for calculating them. Factors affecting these coefficients of interaction were the order in which fisheries operated, amount of overlap in fishing seasons, and intensity of fishing effort by each fishery. We believe that these models could provide useful information for the management of fisheries with multiple user groups where allocation conflicts may arise.}, number={9}, journal={CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES}, author={Brooks, EN and Pollock, KH and Hoenig, JM and Hearn, WS}, year={1998}, month={Sep}, pages={2001–2010} } @article{hoenig_barrowman_pollock_brooks_hearn_polacheck_1998, title={Models for tagging data that allow for incomplete mixing of newly tagged animals}, volume={55}, ISSN={["1205-7533"]}, DOI={10.1139/cjfas-55-6-1477}, number={6}, journal={CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES}, author={Hoenig, JM and Barrowman, NJ and Pollock, KH and Brooks, EN and Hearn, WS and Polacheck, T}, year={1998}, month={Jun}, pages={1477–1483} } @article{hearn_pollock_brooks_1998, title={Pre- and post-season tagging models: estimation of reporting rate and fishing and natural mortality rates}, volume={55}, ISSN={["1205-7533"]}, DOI={10.1139/cjfas-55-1-199}, abstractNote={Brownie et al. (1985, U.S. Fish Wildl. Serv. Resour. Publ. 156, p. 159) presented models for tag returns from multiple taggings of animals when tagging is done twice per year. Here, we present a reformulation of their model suitable for pre- and post-season fishery tag return studies. Under this model, it is possible to estimate fishing mortality, natural mortality, and reporting rate from the tag return data alone. (Under once-a-year tagging models, the reporting rate usually has to be estimated externally.) We consider two special cases: (i) a pulse fishery and (ii) a continuous fishery over part of the year. An artificial example and simulation results are presented to illustrate the methodology and the properties of the various estimators. Unlike for catch-based methods, the correlation between estimates of fishing mortality and natural mortality is moderate. While pre- and post-season tagging studies are likely to be difficult to run in practice, other methods of estimating reporting rate are also difficult to implement, and therefore, this approach may prove quite useful, especially in fisheries that have heavy exploitation rates.}, number={1}, journal={CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES}, author={Hearn, WS and Pollock, KH and Brooks, EN}, year={1998}, month={Jan}, pages={199–205} } @article{hess_brooks_1998, title={The class poster conference as a teaching tool}, volume={27}, number={1998}, journal={Journal of Natural Resources and Life Sciences Education}, author={Hess, G. R. and Brooks, E. N.}, year={1998}, pages={155–158} }