Analysis of blood gases, serum fat and serum protein: a new approach to estimate survival chances of stranded Harbor seal (Phoca vitulina) pups from the German North Sea

Abstract

BackgroundFacing numerous challenges, such as illness, storms or human disturbance, some harbor seal (Phoca vitulina) pups lose contact to their dams and are found abandoned along the North Sea coast. In Schleswig-Holstein, pups with the prospect of surviving rehabilitation are admitted to the Seal Center Friedrichskoog. Despite elaborate clinical health assessments on admission, including differential hematology, in 2010, 17% of 108 admitted pups did not survive the first 20 days. The death rate during the years 2006 and 2009 varied between 9 and 19%. To broaden the spectrum of variables which could be predictive for survival, blood gas and serum analyses were performed for 99 pups using venous blood. Variables included total CO2, pH, partial CO2, HCO3–, base excess and anion gap as well as glucose, urea nitrogen, sodium, potassium and chloride. Moreover, total serum protein and fat (triglyceride) concentrations were measured for all pups on admission.ResultsRepeated measurements of 12 randomly selected individuals revealed a significant (p = 0.002) positive influence of time in rehabilitation on triglyceride concentrations. This trend probably shows the improvement of the pups’ nutritional status as a consequence of the shift from milk replacer formula to fish. No such positive influence was detected for total protein concentrations though. Hematologic values, including blood gases, were not predictive for survival.ConclusionsFor the first time blood gas values are reported in this study for a large sample size (N = 99) of seal pups (regardless of their health status). The ranges and medians calculated from the data can serve as a stepping stone towards the establishment of reference values for neonate harbor seals. However, future investigations on the development of blood gases in harbor seals with different health conditions and ages over time are necessary to allow for a better understanding of acid–base regulation in harbor seals.

Determinants of mortality of juvenile harbour seals (Phoca vitulina) infected with lungworm submitted to a Dutch seal rehabilitation centre

“…To our knowledge, no previous research has been performed on determinants of mortality of juvenile harbour seals (with lungworm) however, there are pre-existing studies of determinants of harbour seal pup survival. Witte et al (2014) evaluated the association between blood gases and survival, but did not find a significant association. Additionally, Greig et al (2010) , discovered an association between two haematological parameters - decreased levels of platelets and decreased levels of protein - and survival, however the resulting models were poor fits to the data.…”

Usefulness of serum cardiac troponin I concentration as a marker of survival of harbor seal (Phoca vitulina) pups during rehabilitation

“…Duration of rehabilitation, body weight, amount of weight gain, and hematologic findings of the seal pups in the present study were similar to those in previous reports. 11,12,14 No CBC or serum biochemical values differed between seal pups that were found to have died and those presumed to have survived rehabilitation. This confirmed the low sensitivity and specificity of CBC and serum biochemical analysis to detect diseased seals and seals at risk of adverse outcomes, consistent with findings in previous reports.…”

“…( J Am Vet Med Assoc 2016;249: [1428][1429][1430][1431][1432][1433][1434][1435] of routine blood testing are frequently unremarkable. [11][12][13][14] Furthermore, age-related changes in CBC and serum biochemical values during rehabilitation need to be considered, [11][12][13][15][16][17] and reference ranges reported for one seal population might not be applicable for another population living in a different environment. 11,12,15,16 More advanced diagnostic methods, such as blood gas analysis 14 and leukocyte function tests, 12 are also unable to identify seals with a greater risk of death than others.…”

The influence of time in captivity, food intake and acute trauma on blood analytes of juvenile Steller sea lions,Eumetopias jubatus

“…Specific to pinnipeds, blood panels provide the backbone of rehabilitation treatment and monitoring and have been assessed for their power to predict survival probability ( Greig et al ., 2010 ; Witte et al , 2014 ). Clinical biochemistry and haematology have been applied to field studies of prey switching in harbour seals ( Thompson et al ., 1997 ) and determining potential physiological differences between genetically distinct populations with opposite trajectories in Steller sea lions ( Zenteno-Savin et al ., 1997 ; Rea et al ., 1998 ; Lander et al , 2013 ).…”