title: Responses of wild freshwater fish to anthropogenic stressors in the Waikato River of New Zealand

authors: West, David William

subjects: fish health

abstract: To assess anthropogenic impacts of point-source and diffuse discharges on fish populations of the Waikato River, compare responses to different discharges and identify potential sentinel fish species, we sampled wild populations of brown bullhead catfish (Ameiurus nebulosus, (LeSueur, 1819)), shortfin eel (Anguilla australis Richardson, 1848), and common bully (Gobiomorphus cotidianus McDowall, 1975) in the Waikato River. Sites upstream and downstream of: geothermal; bleached kraft mill effluent (BKME); sewage and thermal point-source discharges were sampled. At each site, the population parameters, relative abundance, age structure and individual indices such as: condition factor; and organ (gonad, liver, and spleen) somatic weight ratios; and number and size of follicles per female were assessed. Indicators of fish residence and in some cases exposure to contaminants in discharges were analyzed. Bile chemistry of brown bullhead and shortfin eel was assayed, liver and muscle metal levels were analyzed for brown bullhead and shortfin eel respectively, and stable isotopes of C and N in common bully were measured. Bile, metal and isotopic signatures gave strong evidence that fish had been resident at sites for some time before sampling. Signatures of bile and metal contaminants showed contamination was localised to discharge areas. Gradients in stable isotopes in common bully showed evidence of changes in water sources and anthropogenic effects along the river. Biochemical variables, hepatic ethoxyresorufin-O-deethylase (EROD) and plasma steroids indicated exposure and response of brown bullhead and shortfin eel to pulp and paper contaminants at the BKME site.
Physiological (blood) variables showed fish largely responded in a predictable way to elevated water temperatures at discharge sites at time of sampling, however total haemoglobin of brown bullhead and common bully blood failed to increase at the BKME site despite elevated temperatures and low dissolved oxygen. Growth rates, condition factor, age structure, and gonadosomatic index (GSI) suggest that discharges with significant heat or nutrients benefit brown bullhead despite physiological impairment at the BKME site. Shortfin eel individuals also benefited from heated water discharges. No consistent impacts on common bully health were obvious at individual discharge sites, or cumulatively along the river due to the gradual deterioration in water quality downstream. Common bully individuals also benefited from heat in discharges but lack of juveniles at sites where numerous juvenile brown bullhead were found, suggest that unlike brown bullhead populations, common bully populations were not responding with significant recruitment. Although I found little evidence of toxic effects of discharges on shortfin eel, caution is required in assessing the potential of contaminants to impact eel populations due to the life history of shortfin eel, and exploited nature of populations. For example, reproductive damage suffered by adult eels may not immediately manifest itself in the effected population due to temporal delays in gonadal maturation, and recruitment, and single panmictic populations supplementing recruitment of impacted populations.
Distinct changes in population parameters at each of the paired sites and changes in individual variables showed that fish responded to discharges. The range of responses in species suggests different sensitivity to contaminants and amount of benefit which each species receives from heat in discharges. In these terms shortfin eel would be the most resistant, then brown bullhead and lastly common bully. Interpretation of population-level impacts at the geothermal and BKME discharge sites is made difficult due to benefits of additional heat. There is also the possibility that detection of sub-lethal or chronic effects on sensitive juvenile life-stages may be being hidden by compensatory density population responses. Responses and life history of common bully made them the preferred indicator species of the three species sampled, and supported overseas examples using small-bodied fish species as sentinels.

text: Responses of wild freshwater fish to anthropogenic stressors in the Waikato River of New Zealand To assess anthropogenic impacts of point-source and diffuse discharges on fish populations of the Waikato River, compare responses to different discharges and identify potential sentinel fish species, we sampled wild populations of brown bullhead catfish (Ameiurus nebulosus, (LeSueur, 1819)), shortfin eel (Anguilla australis Richardson, 1848), and common bully (Gobiomorphus cotidianus McDowall, 1975) in the Waikato River. Sites upstream and downstream of: geothermal; bleached kraft mill effluent (BKME); sewage and thermal point-source discharges were sampled. At each site, the population parameters, relative abundance, age structure and individual indices such as: condition factor; and organ (gonad, liver, and spleen) somatic weight ratios; and number and size of follicles per female were assessed. Indicators of fish residence and in some cases exposure to contaminants in discharges were analyzed. Bile chemistry of brown bullhead and shortfin eel was assayed, liver and muscle metal levels were analyzed for brown bullhead and shortfin eel respectively, and stable isotopes of C and N in common bully were measured. Bile, metal and isotopic signatures gave strong evidence that fish had been resident at sites for some time before sampling. Signatures of bile and metal contaminants showed contamination was localised to discharge areas. Gradients in stable isotopes in common bully showed evidence of changes in water sources and anthropogenic effects along the river. Biochemical variables, hepatic ethoxyresorufin-O-deethylase (EROD) and plasma steroids indicated exposure and response of brown bullhead and shortfin eel to pulp and paper contaminants at the BKME site.
Physiological (blood) variables showed fish largely responded in a predictable way to elevated water temperatures at discharge sites at time of sampling, however total haemoglobin of brown bullhead and common bully blood failed to increase at the BKME site despite elevated temperatures and low dissolved oxygen. Growth rates, condition factor, age structure, and gonadosomatic index (GSI) suggest that discharges with significant heat or nutrients benefit brown bullhead despite physiological impairment at the BKME site. Shortfin eel individuals also benefited from heated water discharges. No consistent impacts on common bully health were obvious at individual discharge sites, or cumulatively along the river due to the gradual deterioration in water quality downstream. Common bully individuals also benefited from heat in discharges but lack of juveniles at sites where numerous juvenile brown bullhead were found, suggest that unlike brown bullhead populations, common bully populations were not responding with significant recruitment. Although I found little evidence of toxic effects of discharges on shortfin eel, caution is required in assessing the potential of contaminants to impact eel populations due to the life history of shortfin eel, and exploited nature of populations. For example, reproductive damage suffered by adult eels may not immediately manifest itself in the effected population due to temporal delays in gonadal maturation, and recruitment, and single panmictic populations supplementing recruitment of impacted populations.
Distinct changes in population parameters at each of the paired sites and changes in individual variables showed that fish responded to discharges. The range of responses in species suggests different sensitivity to contaminants and amount of benefit which each species receives from heat in discharges. In these terms shortfin eel would be the most resistant, then brown bullhead and lastly common bully. Interpretation of population-level impacts at the geothermal and BKME discharge sites is made difficult due to benefits of additional heat. There is also the possibility that detection of sub-lethal or chronic effects on sensitive juvenile life-stages may be being hidden by compensatory density population responses. Responses and life history of common bully made them the preferred indicator species of the three species sampled, and supported overseas examples using small-bodied fish species as sentinels.

year: 2007

title: The effects of early handling on dairy calves' physiological and behavioural responses to routine husbandry procedures

authors: Shepherd, Haley Marie

subjects: handling

abstract: The quality and quantity of human-animal interactions are crucial to animal welfare, productivity and management of livestock on-farm. Forty Holstein Friesian calves, from one week of age, were exposed to experimental handling for five minutes twice daily for five weeks. Calves were allocated to either positive or negative handling treatments (n=20 per treatment). Positive handling required handlers to slowly approach calves whilst using soft voices to encourage voluntary friendly interactions such as gentle pats. Negative handling consisted of continuous 45 second cycles of direct and indirect handling to discourage friendly interactions. Direct handling required handlers to use fast movements and harsh voices whilst forcibly moving animals around the pen. Indirect handling required handlers to stand in the pen, stare at the animals and tap a polyurethane pipe to make noise to maintain disturbance. Two other novel objects, a plastic bag and an empty water bottle filled with stones, were alternatively used each week to prevent habituation to the negative stimulus. At six weeks of age, all animals were subjected to three routine management procedures: restraint, ear tagging and disbudding, which occurred in stated order over a week period. There were no significant treatment differences between positive and negative groups for heart rate or heart rate variability (measured using Polar heart rate watches), eye temperature (measured using infrared thermography), respiration rates (measured visually), struggling behaviour, and plasma cortisol levels (measured during disbudding only). There were however within treatment differences in response to ear tagging, with an increase in heart rate (p less than 0.01) post-ear tagging, and in response to disbudding with an increase in heart rate (p less than 0.001), tail flicking(p less than 0.001) and cortisol levels (p less than 0.001). It was concluded that, under the conditions of this experiment, early handling does not affect the behavioural and physiological responses of calves to routine management procedures.
In a follow up trial at three months of age, the initial 40 animals and 20 additional three month old minimally handled animals (controls) were assessed for ease of handling using a force test, which ranked the time and effort required to move animals individually into a crush, and an exit speed test which recorded the animals speed exiting the crush, after two minutes of restraint. There were no significant differences between positive, negative and minimally handled treatment groups for heart rate, respiration rates or behaviour in the crush. However, the minimally handled group did appear to be more fearful of humans, with a significantly quicker entry time (p less than 0.05) into the crush than positive and negative treatment groups. There were no differences in entry scores for effort required to move the animals during the force test or for exit speeds. It was concluded that, under the conditions of the present experiment, initial early handling does not appear to cause long lasting effects on calves' behavioural and physiological responses to routine farm management procedures, but minimal contact with humans early in life may lead to a fear of humans later in life.

text: The effects of early handling on dairy calves' physiological and behavioural responses to routine husbandry procedures The quality and quantity of human-animal interactions are crucial to animal welfare, productivity and management of livestock on-farm. Forty Holstein Friesian calves, from one week of age, were exposed to experimental handling for five minutes twice daily for five weeks. Calves were allocated to either positive or negative handling treatments (n=20 per treatment). Positive handling required handlers to slowly approach calves whilst using soft voices to encourage voluntary friendly interactions such as gentle pats. Negative handling consisted of continuous 45 second cycles of direct and indirect handling to discourage friendly interactions. Direct handling required handlers to use fast movements and harsh voices whilst forcibly moving animals around the pen. Indirect handling required handlers to stand in the pen, stare at the animals and tap a polyurethane pipe to make noise to maintain disturbance. Two other novel objects, a plastic bag and an empty water bottle filled with stones, were alternatively used each week to prevent habituation to the negative stimulus. At six weeks of age, all animals were subjected to three routine management procedures: restraint, ear tagging and disbudding, which occurred in stated order over a week period. There were no significant treatment differences between positive and negative groups for heart rate or heart rate variability (measured using Polar heart rate watches), eye temperature (measured using infrared thermography), respiration rates (measured visually), struggling behaviour, and plasma cortisol levels (measured during disbudding only). There were however within treatment differences in response to ear tagging, with an increase in heart rate (p less than 0.01) post-ear tagging, and in response to disbudding with an increase in heart rate (p less than 0.001), tail flicking(p less than 0.001) and cortisol levels (p less than 0.001). It was concluded that, under the conditions of this experiment, early handling does not affect the behavioural and physiological responses of calves to routine management procedures.
In a follow up trial at three months of age, the initial 40 animals and 20 additional three month old minimally handled animals (controls) were assessed for ease of handling using a force test, which ranked the time and effort required to move animals individually into a crush, and an exit speed test which recorded the animals speed exiting the crush, after two minutes of restraint. There were no significant differences between positive, negative and minimally handled treatment groups for heart rate, respiration rates or behaviour in the crush. However, the minimally handled group did appear to be more fearful of humans, with a significantly quicker entry time (p less than 0.05) into the crush than positive and negative treatment groups. There were no differences in entry scores for effort required to move the animals during the force test or for exit speeds. It was concluded that, under the conditions of the present experiment, initial early handling does not appear to cause long lasting effects on calves' behavioural and physiological responses to routine farm management procedures, but minimal contact with humans early in life may lead to a fear of humans later in life.

year: 2010

title: Introduction: Recognition, redistribution and reconciliation in postcolonial settler societies

authors: van Meijl, Toon

subjects: multiculturalism

abstract: Various questions are addressed regarding recognition of special rights for indigenous minorities in postcolonial nation-states, redistributing resources to redress longstanding indigenous grievances about the history of colonial dispossession and strategy of reconciliation between the immigrant majority of settlers and their descendants against a backdrop of multiculturalism.

text: Introduction: Recognition, redistribution and reconciliation in postcolonial settler societies Various questions are addressed regarding recognition of special rights for indigenous minorities in postcolonial nation-states, redistributing resources to redress longstanding indigenous grievances about the history of colonial dispossession and strategy of reconciliation between the immigrant majority of settlers and their descendants against a backdrop of multiculturalism.

year: 2003-09-01