Hunting Regimes Research Articles

Age demographics of a non-breeding Eurasian Woodcock Scolopax rusticola population in relation to environmental factors

ABSTRACT Capsule Environmental conditions in non-breeding areas cause differential winter distribution patterns between age classes in a Eurasian Woodcock Scolopax rusticola population wintering in northern Iberia. Aims To determine the factors driving spatial distribution of first-winter and adult birds in the non-breeding period of a population of the Eurasian Woodcock, in order to make decisions for the management of the species. Methods Using a data set of 10 consecutive winters (2009/10–2018/19), we tested for the effect of year, geographical and habitat-related variables on age ratio and body condition of Eurasian Woodcocks wintering in two nearby zones with different hunting regimes in northern Iberia. Results Our results suggest that the age ratio depended mainly on year, month, and altitude. As winters progressed, we observed a higher proportion of first-winter birds occurring at sites with lower altitude. First-winter birds were in poorer body condition than adults, and body condition was higher in mid-winter and spring. The effect of hunting on body condition was unclear. Discussion Variation in the population structure and body condition between age classes are discussed in the context of age-dependent wintering strategies, which to a large extent depend on survival thresholds that take into account foraging efficiency and the risk of predation. The lack of detectable effects of hunting on age structure and body condition precludes us from giving any management recommendations for northern Iberia.

Between Legal Indigeneity and Indigenous Sovereignty in Taiwan: Insights From Critical Race Theory

Taiwan, home to over 580,000 Indigenous people in 16 state‐recognized groups, is one of three Asian countries to recognize the existence of Indigenous peoples in its jurisdiction. Taiwan’s Indigenous peoples remember their pre‐colonial lives as autonomous nations living according to their own laws and political institutions, asserting that they have never ceded territory or sovereignty to any state. As Taiwan democratized, the state dealt with resurgent Indigenous demands for political autonomy through legal indigeneity, including inclusion in the Constitution since 1997 and subsequent legislation. Yet, in an examination of two court rulings, we find that liberal indigeneity protects individuals, while consistently undermining Indigenous sovereignty. In 2021, the Constitutional Court upheld restrictive laws against hunting, seeking to balance wildlife conservation and cultural rights for Indigenous hunters, but ignoring Indigenous demands to create autonomous hunting regimes. In 2022, the Constitutional Court struck down part of the Indigenous Status Act, which stipulated that any child with one Indigenous parent and one Han Taiwanese parent must use an Indigenous name to obtain Indigenous status and benefit from anti‐discrimination measures. Both rulings deepen state control over Indigenous lives while denying Indigenous peoples the sovereign power to regulate these issues according to their own laws. Critical race theory (CRT) is useful in understanding how legislation designed with good intentions to promote anti‐discrimination can undermine Indigenous sovereignty. Simultaneously, studies of Indigenous resurgence highlight an often‐neglected dimension of CRT—the importance of affirming the nation in the face of systemic racism.

Maternal Transfer and Long-Term Population Effects of PCBs in Baltic Grey Seals Using a New Toxicokinetic–Toxicodynamic Population Model

Empirical evidence has shown that historical exposure of polychlorinated biphenyls (PCBs) to Baltic grey seals not only severely affected individual fitness, but also population growth rates and most likely caused the retarded recovery rate of the depleted population for decades. We constructed a new model which we term a toxicokinetic–toxicodynamic (TKTD) population model to quantify these effects. The toxicokinetic sub-model describes in detail the bioaccumulation, elimination and vertical transfer from mother to offspring of PCBs and is linked to a toxicodynamic model for estimation of PCB-related damage, hazard and stress impacts on fertility and survival rates. Both sub-models were linked to a Leslie matrix population model to calculate changes in population growth rate and age structure, given different rates of PCB exposure. Toxicodynamic model parameters related to reproductive organ lesions were calibrated using published historical data on observed pregnancy rates in Baltic grey seal females. Compared to empirical data, the TKTD population model described well the age-specific bioaccumulation pattern of PCBs in Baltic grey seals, and thus, the toxicokinetic parameters, deduced from the literature, are believed to be reliable. The model also captured well the general effects of PCBs on historical population growth rates. The model showed that reduced fertility due to increased PCB exposure causes decreased vertical transfer from mother to offspring and in turn increased biomagnification in non-breeding females. The developed TKTD model can be used to perform population viability analyses of Baltic grey seals with multiple stressors, also including by-catches and different hunting regimes. The model can also be extended to other marine mammals and other contaminants by adjustments of model parameters and thus provides a test bed in silico for new substances.

La protección de la fauna y el régimen de caza en Uruguay

This article refers to the protection of fauna and the hunting regime in Uruguay. In Uruguay, the protection of fauna and the regulation of hunting have been regulated for many years. Law No. 9481, dated July 4, 1935, continues to be the main legal framework on the subject, regulated by successive decrees. Although these regulations were approved before the appearance of Environmental Law itself, clearly today we shall consider them as norms for the conservation of biodiversity. More recently, the protection of fauna is covered by various environmental management instruments, recognized by article 7 of Law No. 17,283, dated November 28, 2000 (General Environemntal Law), such as the Environmental Impact Assessment (Law No. 16,466, dated January 19, 1994), the National System of Protected Natural Areas (Law No. 17,234, dated February 22, 2000), and land use planning (Law No. 18,308, dated June 18, 2008).

Population reconstruction as an informative tool for monitoring chamois populations

Knowledge of population trends is of key importance for sustainable management of wildlife and finding reliable and cost–effective monitoring methods is therefore of great interest. In two populations of Alpine chamois Rupicapra rupicapra, we collected data on mortality from 12 424 individuals hunted or found dead and population size data based on ground counts over a period of 28 years. Our study had three aims: 1) we investigated if changes in population size obtained with a simple deterministic population reconstruction (DPR) approach using hunting and natural mortality covary with population size estimates obtained from ground count data. 2) We investigated if the performance of DPR is affected by the removal of natural mortality data. 3) We assessed how many years of mortality data are needed to obtain consistent population trends using DPR. Our results suggested that 1) population abundance from mortality data using DPR significantly and positively correlated with population abundance obtained with ground counts. 2) DPR without natural mortality data performed similarly as compared to DPR using full data (hunting and natural mortality). 3) Consistent estimates of population trends can be obtained with ≥10 years of mortality data, however, this time span was influenced by the mean age at death, which in turn was affected by the local hunting regime. Our results suggest that DPR and ground counts perform similarly for the estimation of temporal trends in Alpine chamois abundance. The consistence of ground counts and DPR supports the use of these methods as reliable tools for tracking abundance of chamois populations over time. However, the reliability of abundance estimates using DPR may vary between populations and the influence of different hunting regimes must be considered for the correct interpretation of results.

How climate change and wildlife management affect population structure in wild boars

Global climate change affects many species and contributes to the exceptional population growth of wild boar populations and thus to increasing human-wildlife conflicts. To investigate the impact of climate change on wild boar populations we extended existing models on population dynamics. We included for the first time different juvenile conditions to account for long-lasting effects of juvenile body mass on adult body mass and reproductive success. Our analysis shows that incorporating phenotypes, like body mass differences within age classes, has strong effects on projected population growth rates, population structures and the relative importance of certain vital rates. Our models indicated that an increase in winter temperatures and food availability will cause a decrease in mean body mass and litter size within Central European wild boar populations. We further analysed different hunting regimes to identify their effects on the population structure as well as their efficiency in limiting population growth. While targeting juveniles had the lowest effect on population structure, such strategies are, however, rather ineffective. In contrast, culling predominantly yearlings seems very effective. Despite being equally effective, only focusing on adults will not result in a reduction of population size due to their low proportion within populations.

Contrasting patterns of sexually selected traits in Mediterranean and continental populations of European mouflon.

The expression of sexually selected traits in highly dimorphic ungulates may be influenced by environmental quality. Variations in habitat conditions can impose different constraints on the allocation of energy resources to male life‐history traits, and possibly alter the female preferences for specific features. Here, we compared the horn growth patterns in male European mouflon Ovis aries musimon living in different habitats (Mediterranean vs. continental) but sharing a common genetic origin. We hypothesized that the expression of sexually selected traits such as horn development should be promoted in more favorable habitat conditions (i.e., Mediterranean). Using linear mixed models on data retrieved from individuals harvested under the same hunting regime, we found longer horns and greater individual variance in horn segment length in the Mediterranean population than in the continental one. Furthermore, Mediterranean rams showed no evidence of compensatory horn growth, as opposed to the continental rams. Unexpectedly, horn base circumference was greater in the continental habitat than in the Mediterranean one. The overall results suggest different patterns of investment in horns in the two populations, with seemingly stronger pressure and consequences of sexual selection on mouflon rams living in more favorable environments. Although the role of hunters' selectivity cannot be excluded a priori, our data suggest that the differences in the expression of sexually selected traits in our study populations may be influenced by environmental conditions. Because sexual selection can impose substantial fitness costs on individuals, further investigations on the trade‐offs between reproduction and survival would improve our understanding of the dynamics of mouflon populations living in different environmental conditions.

Adaptation of wild boar (Sus scrofa) activity in a human-dominated landscape

BackgroundWild boars (Sus scrofa L.) are globally widely distributed, and their populations have increased in Europe during recent decades. Encounters between humans and wild boars are rare because of the predominantly nocturnal lifestyle of the latter, and wild boar management by hunting is a challenging task. Animal activity patterns are important for understanding the behaviour of a species. However, knowledge of detailed temporal patterns and an understanding of the drivers of wild boar activity at a fine temporal scale are lacking. Of special relevance for human–wild boar interactions (e.g., encounters, conflicts, and management) is the question of whether nocturnal activity depends on anthropogenic factors and, particularly, how local hunting regimes may affect activity patterns. We used GPS telemetry and acceleration measurements to shed light on this part of wild boar behaviour, observing 34 animals in Central Europe. Animals were tracked along a gradient of hunting pressure from hunting-free areas to areas with low or high hunting pressure. Fitted generalised additive models allowed predicting the probability of active behaviour under differing disturbance regimes precisely to day of year and time of day.ResultsThe wild boars were predominantly nocturnal, with peak activity at approximately midnight. However, the data showed increased activity during daylight for wild boars that used no-hunting zones or reduced-hunting zones. Large areas with low disturbance levels promoted activity during daylight more than smaller areas with an intermediate disturbance regime. High air temperatures and locations within forests reduced the probability of active behaviour, whereas proximity to tracks used for forestry or agriculture was accompanied by a higher probability of activity.ConclusionsWe conclude that wild boars flexibly adjust their activity to their local environmental conditions, considering disturbances at the scale of long-term home ranges as well as actual small-scale landscape quality. Entire wild boar home ranges should be covered in the delineation of reserves intending to stimulate activity during daylight.

Integrating cultural and biological perspectives on long-term human-walrus (Odobenus rosmarus rosmarus) interactions across the North Atlantic

AbstractThe hunting of marine mammals as a source of subsistence, trade, and commercial revenue has formed an important part of human cultures across the North Atlantic. One important prey species has been the Atlantic walrus (Odobenus rosmarus rosmarus), sought after for meat, skin, blubber, ivory, and bone. Unfortunately, biological studies of current walrus populations and studies across the humanities and social sciences into past use and hunting of walruses, have been poorly integrated. Disciplinary boundaries have left a gap in understanding the reciprocal effects of human-walrus interactions. Emerging interdisciplinary methods offer new opportunities to write the historical ecology of Atlantic walruses. The integration of methods such as ancient DNA, isotopes, past population modelling, zooarchaeological assemblages, and ethnographic interviews can now be used to answer previously intractable questions. For example, how has walrus hunting shaped and been influenced by changes in human settlement and trade, what have been the cumulative impacts on walrus populations, the extent of anthropogenic selective pressures or the effect of changing hunting regimes on particular populations of walruses? New, collaborative research approaches applied to the wealth of Arctic archaeological faunal remains already housed in museum collections offer a unique chance to explore the past dynamics of human-animal interactions.

Survival probabilities of wintering Eurasian Woodcocks Scolopax rusticola in northern Spain reveal a direct link with hunting regimes

The management of game species relies on robust estimates of hunting-related mortality. A relative measure of this mortality can be obtained by comparing survival estimates of animals across similar areas with different hunting pressures. We conducted live recapture-dead recovery analyses on wintering Eurasian Woodcocks Scolopax rusticola (hereinafter “Woodcock”) in provinces of Gipuzkoa (GIP) and Alava (ALA), two neighboring regions of northern Spain. The two regions have a similar number of hunting licences issued on a per day basis, but while hunting is limited to 3 days per week in ALA, in GIP it is allowed on a daily basis, resulting in a ca. 50% longer period of exposure of game species to hunting-related mortality here. We used a model based on monthly survival estimates to test whether the mortality of Woodcock varied between the two regions. Mean (± SE from a time-constant model) annual survival of Woodcocks was estimated to be 0.37 (± 0.04) and 0.56 (± 0.04) in GIP and ALA, respectively. If we assumed that this difference was only due to the longer period of exposure to hunting, mortality was increased by ca. 10% per additional day of hunting per week. Moreover, we also found that survival was positively associated with temperature in one of the study zones (ALA), suggesting that a high hunting pressure can override the effect of climate-dependent fluctuations. However, further research into fecundity and dispersal is necessary to assess the viability and sustainability of the wintering Woodcock populations under the current hunting regimes in these two zones.

Estimating red deer (Cervus elaphus) population size in the Southern Black Forest: the role of hunting in population control

Numerous studies have addressed the question of whether hunting is capable of limiting the abundance of ungulates in the northern hemisphere. We investigated whether the hunting of red deer (Cervus elaphus) has reduced their abundance in the Southern Black Forest (area 17,500 ha), Southern Germany, since 2006. Red deer abundance was estimated using data obtained from visual counts at winter feeding sites, track counts, and bag records. An age- and sex-structured population model to estimate the winter population size was also constructed using bag records. The estimated red deer population size was evaluated according to a non-invasive genetic mark-recapture approach. The results showed that the hunting of red deer can reduce their population size if the hunting regime is part of a holistic management concept that takes into account the uncertainty of population size estimates and is implemented at scales appropriate to the management of this species.

Large herbivores in novel ecosystems - Habitat selection by red deer (Cervus elaphus) in a former brown-coal mining area.

After centuries of range contraction, many megafauna species are recolonizing parts of Europe. One example is the red deer (Cervus elaphus), which was able to expand its range and is now found in half the areas it inhabited in the beginning of the 19th century. Herbivores are important ecosystem engineers, influencing e.g. vegetation. Knowledge on their habitat selection and their influence on ecosystems might be crucial for future landscape management, especially for hybrid and novel ecosystems emerging in post-industrial landscapes. In this study, red deer habitat selection was studied in a former brown-coal mining area in Denmark. Here, natural settings were severely changed during the mining activity and its current landscape is in large parts managed by hunters as suitable deer habitat. We assessed red deer habitat preferences through feces presence and camera traps combined with land cover data from vegetation sampling, remote sensing and official geographic data. Red deer occurrence was negatively associated with human disturbance and positively associated with forage availability, tree cover and mean terrain height. Apparently, red deer are capable of recolonizing former industrial landscapes quite well if key conditions such as forage abundance and cover are appropriate. In the absence of carnivores, human disturbance, such as a hunting regime is a main reason why deer avoid certain areas. The resulting spatial heterogeneity red deer showed in their habitat use of the study area might be a tool to preserve mosaic landscapes of forest and open habitats and thus promote biodiversity in abandoned post-industrial landscapes.

Does selection on horn length of males and females differ in protected and hunted populations of a weakly dimorphic ungulate?

Weaponry in ungulates may be costly to grow and maintain, and different selective pressures in males and females may lead to sex‐biased natural survival. Sexual differences in the relationship between weapon growth and survival may increase under anthropogenic selection through culling, for example because of trophy hunting. Selection on weaponry growth under different scenarios has been largely investigated in males of highly dimorphic ungulates, for which survival costs (either natural or hunting related) are thought to be greatest. Little is known, however, about the survival costs of weaponry in males and females of weakly dimorphic species. We collected information on horn length and age at death/shooting of 407 chamois Rupicapra rupicapra in a protected population and in two hunted populations with different hunting regimes, to explore sexual differences in the selection on early horn growth under contrasting selective pressures. We also investigated the variation of horn growth and body mass in yearling males (n = 688) and females (n = 539) culled in one of the hunted populations over 14 years. The relationship between horn growth and survival showed remarkable sexual differences under different evolutionary scenarios. Within the protected population, under natural selection, we found no significant trade‐off in either males or females. Under anthropogenic pressure, selection on early horn growth of culled individuals showed diametrically opposed sex‐biased patterns, depending on the culling regime and hunters’ preferences. Despite the selective bias between males and females in one of the hunted populations, we did not detect significant sex‐specific differences in the long‐term pattern of early growth. The relationship between early horn growth and natural survival in either sex might suggest stabilizing selection on horn size in chamois. Selection through culling can be strongly sex‐biased also in weakly dimorphic species, depending on hunters’ preferences and hunting regulations, and long‐term data are needed to reveal potential undesirable evolutionary consequences.

Modeling the distribution of Apennine brown bears during hyperphagia to reduce the impact of wild boar hunting

The Apennine brown bear (Ursus arctos marsicanus) survives today in a relict population of about 50 bears in the central Apennines, even though they have been long protected and habitat suitability at the landscape scale does not appear to be a limiting factor for population recovery. Multiple uses within the bear range may increase disturbance and chances of human-caused mortality, including wild boar hunting drives with dogs conducted in the fall and coinciding with hyperphagia in bears. Although wild boar hunting drives represent a very popular recreational activity throughout the central Apennines, this is a very invasive practice and is thought to exert both direct and indirect detrimental effects on bears. In order to foster the progressive abandonment of wild boar hunting drives in the bear range in favor of less impacting hunting methods, we developed a species distribution model (SDM) to identify areas of likely bear presence during hyperphagia. This SDM could represent the basis to develop a hunting zoning system useful to modulate wild boar hunting regimes according to the bear occurrence. Starting from a large dataset of bear occurrences collected from September to November (2005–2010) within the core distribution range of the bear (n = 5746 GPS- and VHF-telemetry locations on 25 adult and subadult bears, plus other signs of bear presence), we modeled the distribution of bears during hyperphagia and selected candidate models using second order corrected Akaike information criteria (AICc). The final model included 16 environmental, topographic, and anthropogenic variables and was evaluated using the continuous Boyce index (0.91). By intersecting the bear occurrence model with a proxy of wild boar hunting intensity, we identified the areas where the banning of wild boar hunting drives represents a priority, and where less impacting hunting regimes are urgently needed. By discussing how such a model can be used to facilitate consensus toward alternative hunting management scenarios, we believe our approach can be extended to other small populations of bears, and of other species as well, that live in multiple-use landscapes and are in need of recovery.

Annual and seasonal survival of adult female Mottled Ducks in southern Florida, USA

Continuing human population growth and urbanization in Florida may impact the survival of native birds, including the Florida Mottled Duck (Anas fulvigula fulvigula). Survival of adult females is an important vital rate that affects population growth rates, thus estimates of female survival as well as sources of variation affecting survival rates are needed for the development of a more informed conservation plan for Florida Mottled Ducks. In this study, we estimated annual and seasonal survival rates of radio-tagged adult female Mottled Ducks (n = 236) using urban and rural areas in southern Florida from 2008 to 2011. Additionally, we tested for differences in survival among ducks using different geographic areas during the breeding season and that were exposed to different hunting regimes during the hunting season. Identifying the geographic areas where higher rates of mortality occur may allow for more effective habitat and harvest management of the Florida subspecies of Mottled Duck. Annual survival was higher for ducks that used urban areas (74%) than for ducks that did not (47%). Daily survival rates were lowest during the breeding season. Females that used Everglades-type habitat during the breeding season had higher seasonal survival rates (78–85%) than those that did not (37–47%). We found evidence of density-dependent mortality during and after the hunting season. Differences in hunting season survival for ducks that used unhunted rural areas (88%) when compared with survival of ducks that used areas with open (87%) or quota hunting systems (85%) were not significant. Differences in survival among study years were negligible. Our results indicate that Florida Mottled Ducks survive at high rates in urbanized areas, but may benefit from increases in the quantity and quality of breeding habitats.

Of Boars and Men: Indigenous Knowledge and Co-Management in Taiwan

Around the world, especially since the passage of the UN Declaration on the Rights of Indigenous Peoples in 2007, indigenous people have hoped that advances in legal rights can help them gain recognition for their ecological knowledge and autonomy in the use of natural resources. In Taiwan, following legal changes in the 2005 Basic Law on Indigenous Peoples, indigenous people hope to gain control of their own hunting regime through establishment of co-management boards with national parks and other state institutions on their traditional territories. This article explores hunting practices and indigenous knowledge in Truku communities. Hunters and trappers possess rich knowledge about the mammals and birds of the forests. Hunting practices embed them in the ancestral law of Gaya and contribute to cultural survival. This article explores whose knowledge is most relevant to the establishment of co-management institutions and makes suggestions for their creation.

Do bears know they are being hunted?

Behavioral effects of living under predation risk may influence the dynamics of prey species more than direct demographic effects. Human recreation, especially hunting, can also force prey to increase their vigilance and can influence distribution and habitat use even more than natural predators. However, behavioral effects do not play a prominent role in conservation or wildlife management. Whereas the demographic consequences of hunting are documented for large carnivores, behavioral effects of hunting on their dynamics remain unexplored. We studied the movement patterns of brown bears (Ursus arctos) in Scandinavia as a model species, before and after the start of the annual bear hunting season. Bears were expected to become more active at daytime as the season progressed due to shortening daylight. However, the start of hunting disrupted this pattern. Solitary bears subject to hunting increased movements during the dark hours after hunting started, losing their nocturnal rest, probably to compensate for decreased daytime activity. Females with cubs-of-the-year, which are protected from hunting, also modified their movement pattern, but much less than hunted bears. Bears altered their movement pattern at a critical time of the year, during hyperphagia, when they must store fat reserves before hibernation, which is critical for reproduction. Behavioral effects of hunting should be a relevant issue for the conservation and management of large carnivores, especially when hunting occurs during highly sensitive periods of the year. This concern applies to many species managed under hunting regimes.

Estimating wild boar Sus scrofa population size using faecal DNA and capture‐recapture modelling

Increasing populations of wild boar and feral domestic pigs Sus scrofa have evoked growing concern due to their potential as disease reservoir and as an origin of agricultural damages. Reliable population estimates are needed for effective management measures of this species. As an alternative to traditional methods, non‐invasive genetic population estimation approaches based on hair or faeces sampling have yielded promising results for several species in terms of feasibility and precision. We developed and applied a non‐invasive population estimation approach based on wild boar faeces in a study area situated in the Palatinate Forest, southwestern Germany. We collected 515 faeces samples along transects in January 2008. We carried out genotyping using six microsatellite markers to discriminate between individuals. During the trial, we identified 149 individual wild boar. Using multimodel inference and model averaging, we obtained relatively consistent estimates. Population densities calculated using the estimated population sizes ranged from 4.5 (2.9‐7.8) to 5.0 (4.0‐7.0) wild boar/km2. In the future, to further improve the precision of population estimates based on wild boar faeces, the detection probability should be increased. However, even when comparing a conservative population estimate to the hunting bag, our results show that the present hunting regime in our study area is not effective in regulating the wild boar population. The method which we present here offers a tool to calibrate hunting or other management measures for wild boar.

Does illegal hunting skew Serengeti wildlife sex ratios?

AbstractIn this article we show that the population of Serengeti Masai giraffes Giraffa camelopardalis tippelskirchi is extremely female biased, particularly among newborns. Our results suggest that this might be a response to heavy illegal hunting and the continuous disturbance such activities cause on giraffes, as sex ratios were more female skewed in all age groups in areas with high risk of illegal hunting. Giraffes were also more vigilant and fled at longer distances in such areas. Such female skewed sex ratios have also been found in other Serengeti species such as the ostrich Struthio camelus, the impala Aepycerus melampus and the wildebeest Connochaetus taurinus. In all studies, the sex ratio was more female skewed in areas in which illegal hunting is common. We found that sex ratio in giraffe calves, particularly in areas with high risk of illegal hunting, were more female skewed than in subadults or adults, indicating a female biased sex ratio at birth. If wildlife species react to a constant human disturbance by conceiving female offspring, this might cause serious conservation challenges. Conservation managers must anyway take this into account when developing future hunting regimes, not only for giraffes but also for other ungulate species under constant stress. We discuss various hypotheses aiming at explaining the female biased sex ratio in giraffes. However, further studies are needed to disentangle the causes of the skewed sex ratio observed in our study.

Microsatellite and mtDNA analysis of the population structure of grey seals (Halichoerus grypus) from three breeding areas in the Baltic Sea

The growing number of grey seals in the Baltic Sea has led to a dramatic increase in interactions between seals and fisheries. The conflict has become such a problem that hunting was introduced in Finland in 1998 and the Swedish Environment Protection Agency recommended a cull of grey seals starting in 2001. Culling has been implemented despite the lack of data on population structure. Low levels of migration between regions would mean that intensive culling in specific geographic areas would have disproportionate effects on local population structure and genetic diversity. We used eight microsatellite loci and a 489 bp section of the mtDNA control region to examine the genetic variability and differentiation between three breeding sites in the Baltic Sea and two in the UK. We found high levels of genetic variability in all sampled Baltic groups for both the microsatellites and the control region. There were highly significant differences in microsatellite allele frequencies between all three Baltic breeding sites and between the Baltic sites and the UK sites. However, there were no significant differences in mtDNA control region haplotypes between the Baltic sites. This genetic substructure of the Baltic grey seal populations should be taken into consideration when managing the seal population to prevent the hunting regime from having an adverse effect on genetic diversity by setting hunting quotas separately for the different subpopulations.